A 60 kg skler goes down a 20 m high hill, starting from rest. a) (2 pts) The skier assumes that all the forces acting on them are conservative forces. Is this a reasonable assumption? b) (6 pts) When they are at a height of 8 m, they notice their speed is 12 m/s. Was their assumption from part a) correct? Use physics (numbers) to support your answer.

To transmit 25 kW at 720 rpm on an aluminum rolling machine, a cross belt drive with a tension of 484 N would be needed, considering the given parameters and the coefficient of friction in the belt.

To design a cross belt drive to transmit 25 kW at 720 rpm on an aluminum rolling machine, we need to consider various factors such as speed reduction, distance between the shaft and the motor, pulley dimensions, coefficient of friction in the belt, and allowable stress coefficient.

First, let's calculate the speed of the driven pulley. Since the speed reduction is 3.0, the speed of the driven pulley would be 720 rpm / 3.0 = 240 rpm.

Next, let's calculate the belt velocity. The belt velocity can be determined by multiplying the diameter of the driven pulley by π and the speed of the driven pulley. Therefore, the belt velocity is (1.2 m / 2) * π * 240 rpm = 452.39 m/min.

To find the power transmitted by the belt, we divide the given power by the belt velocity. Thus, the power transmitted by the belt is 25,000 W / 452.39 m/min = 55.21 Nm/s.

Using the equation for power transmission through friction, P = (T1 - T2) * V, where P is power, T1 and T2 are tensions in the belt, and V is the belt velocity, we can rearrange the equation to solve for T2:

T2 = T1 - (P / V)

Substituting the values, T2 = T1 - (55.21 Nm/s / 452.39 m/min) = T1 - 0.122 N.

Considering the allowable stress coefficient of 2 MPa, we can calculate the allowable tension in the belt:

Allowable tension (Tall) = (2 MPa * π * (350 mm / 2)^2) / 1,000 = 96.78 N

Finally, we can find the required tension in the belt (T1) using the coefficient of friction:

T1 = (Tall + T2) / (2 * friction coefficient) = (96.78 N + 0.122 N) / (2 * 0.2) = 484 N

Therefore, the required tension in the belt is 484 N.

In summary, to transmit 25 kW at 720 rpm on an aluminum rolling machine, a cross belt drive with a tension of 484 N would be needed, considering the given parameters and the coefficient of friction in the belt.

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You would need to be approximately 3.33 km away from Chernobyl to reach a safe radiation level. We can use the concept of inverse square law for radiation.

To determine the distance you need to be from Chernobyl to reach a safe radiation level, we can use the concept of inverse square law for radiation.

The inverse square law states that the intensity of radiation decreases with the square of the distance from the source. Mathematically, it can be expressed as:

I₁/I₂ = (d₂/d₁)²

where I₁ and I₂ are the radiation intensities at distances d₁ and d₂ from the source, respectively.

In this case, we can set up the following equation:

900/100 = (10/d)²

Simplifying the equation, we have:

9 = (10/d)²

Taking the square root of both sides, we get:

3 = 10/d

Cross-multiplying, we find:

3d = 10

Solving for d, we get:

d = 10/3

Therefore, you would need to be approximately 3.33 km away from Chernobyl to reach a safe radiation level.

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The reading on the ammeter would be approximately 2.14 Amperes.

To calculate the reading on the ammeter, we need to determine the resistance of the 14 AWG iron wire. The resistance can be calculated using the formula

[tex]R = ρ * (L / A)[/tex]

where:

R is the resistance,

ρ is the resistivity of the material (in this case, iron),

L is the length of the wire, and

A is the cross-sectional area of the wire.

First, let's calculate the cross-sectional area of the 14 AWG wire. The diameter of the wire can be obtained from the wire gauge size. For 14 AWG, the diameter is approximately 1.628 mm.

The radius (r) can be calculated by dividing the diameter by 2:

r = 1.628 mm / 2 = 0.814 mm = 0.000814 m

The cross-sectional area (A) can be calculated using the formula:

[tex]R = ρ * (L / A)[/tex]

[tex]A = 3.14159 * (0.000814 m)^2 ≈ 2.07678 × 10^(-6) m^2[/tex]

Next, we need to find the resistivity of iron. The resistivity of iron (ρ) is approximately 9.71 × 10^(-8) Ω·m.

Now, we can calculate the resistance (R) using the formula mentioned earlier:

[tex]R = (9.71 × 10^(-8) Ω·m) * (100 m / 2.07678 × 10^(-6) m^2)[/tex]

[tex]R ≈ 4.675 Ω[/tex]

Therefore, with a 10 V potential difference across the 14 AWG iron wire resistor, the reading on the ammeter would be:

[tex]I = V / R[/tex]

[tex]I = 10 V / 4.675 Ω[/tex]

[tex]I ≈ 2.14 A[/tex]

So, the reading on the ammeter would be approximately 2.14 Amperes.

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Approximately 0.022 kg of ice melts into water at 0 °C. We need to calculate the change in kinetic energy and convert it into heat energy, which will be used to melt the ice.

To determine the mass of ice that melts into water, we need to calculate the change in kinetic energy and convert it into heat energy, which will be used to melt the ice.

The initial kinetic energy of the ice block is given by:

KE_initial = (1/2) * mass * velocity_initial^2

The final kinetic energy of the ice block is given by:

KE_final = (1/2) * mass * velocity_final^2

The change in kinetic energy is:

ΔKE = KE_final - KE_initial

Assuming all the heat generated by kinetic friction is used to melt the ice, the heat energy is given by:

Q = ΔKE

The heat energy required to melt a certain mass of ice into water is given by the heat of fusion (Q_fusion), which is the amount of heat required to change the state of a substance without changing its temperature. For ice, the heat of fusion is 334,000 J/kg.

So, we can equate the heat energy to the heat of fusion and solve for the mass of ice:

Q = Q_fusion * mass_melted

ΔKE = Q_fusion * mass_melted

Substituting the values, we have:

(1/2) * mass * velocity_final^2 - (1/2) * mass * velocity_initial^2 = 334,000 J/kg * mass_melted

Simplifying the equation:

(1/2) * mass * (velocity_final^2 - velocity_initial^2) = 334,000 J/kg * mass_melted

Now we can solve for the mass of ice melted:

mass_melted = (1/2) * mass * (velocity_final^2 - velocity_initial^2) / 334,000 J/kg

Substituting the given values:

mass_melted = (1/2) * 41.1 kg * (3.10 m/s)^2 - (6.79 m/s)^2) / 334,000 J/kg

Calculating the value, we get:

mass_melted ≈ 0.022 kg

Therefore, approximately 0.022 kg of ice melts into water at 0 °C.

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The value of the sound intensity on a busy road, expressed in dB, is approximately 83 dB.

We can calculate the value of the sound intensity in dB using the formula I(dB) = 10 log10(I/I0), where I is the sound intensity and I0 is the reference intensity of 10^(-12) W/m².

Given that the sound intensity on a busy road is I = 3 x 10^(-5) W/m², we can substitute these values into the formula:

I(dB) = 10 log10((3 x 10^(-5)) / (10^(-12)))

Simplifying this, we have:

I(dB) = 10 log10(3 x 10^7)

Using the logarithmic property log10(a x b) = log10(a) + log10(b), we can further simplify:

I(dB) = 10 (log10(3) + log10(10^7))

Since log10(10^7) = 7, we have:

I(dB) = 10 (log10(3) + 7)

Using a calculator, we can evaluate log10(3) + 7 and then multiply it by 10 to obtain the final result:

I(dB) ≈ 83 dB

Therefore, the value of the sound intensity on a busy road, expressed in dB, is approximately 83 dB.

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The maximum height is 122.5 meters when a stone is thrown vertically upward.

Time is taken to reach the maximum height = 5 seconds

Acceleration due to gravity= -9.8 m/ second squared

After reaching the max height,  its final velocity is zero. It is written as:

v = u + a*t

Assuming the final velocity is Zero.

0 = u + a*t

u = -a*t

u = -([tex]-9.8 m/s^2[/tex]) * 5 seconds

u = 49 m/s

The displacement formula is used to calculate the maximum height:

s = ut + (1/2)*[tex]at^2[/tex]

s = 49 m/s * 5 seconds + [tex](1/2)(-9.8 m/s^2)*(5 seconds)^2[/tex]

s = 245 m - 122.5 m

s = 122.5 m

Therefore, we can conclude that the maximum height is 122.5 meters.

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The angle between the two beams inside the glass for blue light is approximately 17.65°, and for red light is approximately 19.10°.

To determine the angle between the two beams inside the glass, we can use Snell's Law, which relates the angles of incidence and refraction to the indices of refraction of the two media:

n₁sinθ₁ = n₂sinθ₂

Where:

n₁ = index of refraction of the initial medium (air)

θ₁ = angle of incidence in the initial medium

n₂ = index of refraction of the final medium (glass)

θ₂ = angle of refraction in the final medium

n₁ = 1 (index of refraction of air)

n₂ (for blue light) = 1.660

n₂ (for red light) = 1.600

θ₁ = 30.0° (angle of incidence)

For blue light (wavelength = 420 nm):

n₁sinθ₁ = n₂sinθ₂

(1)(sin 30.0°) = (1.660)(sin θ₂)

Solving for θ₂, we find:

sin θ₂ = (sin 30.0°) / 1.660

θ₂ = arcsin[(sin 30.0°) / 1.660]

Using a calculator, we find:

θ₂ ≈ 17.65°

For red light (wavelength = 600 nm):

n₁sinθ₁ = n₂sinθ₂

(1)(sin 30.0°) = (1.600)(sin θ₂)

Solving for θ₂, we find:

sin θ₂ = (sin 30.0°) / 1.600

θ₂ = arcsin[(sin 30.0°) / 1.600]

Using a calculator, we find:

θ₂ ≈ 19.10°

Therefore, the angle between the two beams inside the glass for blue light is approximately 17.65°, and for red light is approximately 19.10°.

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The correct answer is (d) 1.5 A.

The current through a resistor connected to a battery can be calculated using Ohm's Law, which states that the current  (I) flowing through a resistor is equal to the voltage (V) across the resistor divided by its resistance (R). Mathematically, it can be expressed as I = V/R.

In this case, the voltage across the resistor is given as 1.5 V, and the resistance is 1.0 kΩ (which is equivalent to 1000 Ω). Plugging these values into Ohm's Law, we get I = 1.5 V / 1000 Ω = 0.0015 A = 1.5 A.

Therefore, the current through the 1.0 kΩ resistor connected to the 1.5 V battery is 1.5 A.

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The expression for the image distance di in terms of the object distance do and the radius of curvature r is di = 1 / (2/r - 1/6.8).

The expression for the image distance in terms of the object distance, radius of curvature, and focal length can be determined using the mirror equation for concave mirrors. The mirror equation states that 1/f = 1/do + 1/di, where f is the focal length, do is the object distance, and di is the image distance.

In this case, we are given the object distance do = 6.8 cm and the radius of curvature r = 17.3 cm. The focal length of a concave mirror is half the radius of curvature, so f = r/2.

Substituting the given values into the mirror equation, we have:

1/(r/2) = 1/6.8 + 1/di

Simplifying, we get:

2/r = 1/6.8 + 1/di

To find the expression for the image distance di, we can rearrange the equation:

1/di = 2/r - 1/6.8

Taking the reciprocal of both sides, we have:

di = 1 / (2/r - 1/6.8)

Therefore, the expression for the image distance di in terms of the object distance do and the radius of curvature r is di = 1 / (2/r - 1/6.8).

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When a piece of iron block moves across a rough

horizontal surface

before coming to rest, its initial speed, mass, and specific heat can be used to calculate how much the block's temperature increases after absorbing 69% of its initial kinetic energy as internal energy. The following is the solution:According to the law of conservation of energy, the sum of the initial kinetic energy (KEi) and the initial potential energy (PEi) of a system equals the sum of the final kinetic energy (KEf), potential energy (PEf), and internal energy (U) of the system.

The sum of the initial

kinetic energy

and potential energy of the block can be written as KEi + PEi = mgh + (1/2)mv², where m is the mass of the block, g is the acceleration due to gravity, h is the height of the block, and v is the initial speed of the block. Since the block is on a horizontal surface, h = 0, and the equation reduces to KEi + PEi = (1/2)mv².KEi + PEi = (1/2)mv² = (1/2)(1.3 kg)(2.00 m/s)² = 2.6 J.

The sum of the final kinetic energy, potential energy, and internal energy of the block can be written as KEf + PEf + U, where KEf = 0, PEf = mgh = 0, and U is the internal energy gained by the block.KEf + PEf + U = 0 + 0 + U = 0.69(KEi + PEi) = 0.69(2.6 J) = 1.794 J.The internal energy gained by the block is equal to the amount of energy that it absorbed from its initial kinetic energy, which can be written as ΔU = mcΔT, where c is the specific heat of iron and ΔT is the change in temperature of the block.ΔU = mcΔT = 1.794 J = (1.30 kg)(452 J/(kg • °C))ΔT, so ΔT = 2.98°C.Therefore, the temperature of the iron block increases by 2.98°C after absorbing 69% of its initial kinetic energy as

internal energy

.

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The fraction of the Earth's 100 TW biological budget justifiably used for human energy needs depends on ecological impact, sustainability, and ethical considerations. Renewable energy sources are generally considered more justifiable.

The biological budget of the Earth, which refers to the total amount of energy captured by photosynthesis and used by all living organisms on the planet, is estimated to be around 100 terawatts (TW) (Smil, 2002). However, it's important to note that this energy is not solely available for human use, as it also supports the survival and functioning of all other living organisms on the planet.

The fraction of the biological budget that can be justifiably used for human energy needs is a complex question that depends on various factors, including the ecological impact of human use, the sustainability of energy use practices, and the societal and ethical considerations involved.

In general, renewable energy sources such as solar, wind, hydro, and geothermal are considered to be more sustainable and environmentally friendly than non-renewable sources such as fossil fuels. Therefore, it may be more justifiable to use a larger fraction of the biological budget for renewable energy sources than for non-renewable sources.

Currently, human energy use is estimated to be around 18 TW (International Energy Agency, 2021), which is only a fraction of the total biological budget. However, as the global population and energy demand continue to grow, it's important to consider ways to reduce energy consumption and improve the efficiency of energy use to minimize the impact on the environment and ensure the sustainability of energy sources for future generations.

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The specific heat capacity of copper is 0.888 kJ/(kg × °C).

Specific heat capacity is a thermal property of a substance. It indicates how much heat energy is needed to raise the temperature of a unit mass of a substance by one degree Celsius.

The formula for calculating the specific heat capacity of a substance is given as, q = m × c × ∆T`

Where: q = energy,

m = mass of the substance,

c = specific heat capacity of the substance,

∆T = change in temperature.

Now, let’s use the formula above to calculate the specific heat capacity of copper.

The energy required to raise the temperature of a 1 kg block of copper by 10°C is 8.88 kJ.

q = m × c × ∆T

c = q / (m × ∆T)

= 8.88 kJ / (1 kg × 10°C)

= 0.888 kJ/(kg × °C)

The specific heat capacity of copper is 0.888 kJ/(kg × °C).

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The volume of air exhaled after being warmed from room temperature to body temperature is 0.59 L.

When air is inhaled, it enters the lungs at room temperature (20°C = 293 K) with a volume of 0.6 L. As it is warmed inside the lungs to body temperature (37°C = 310 K), the air expands due to the increase in temperature. According to Charles's Law, the volume of a gas is directly proportional to its temperature, assuming constant pressure. Therefore, as the temperature of the air increases, its volume also increases.

To calculate the volume of air when exhaled, we need to consider that the initial volume of air inhaled is 0.6 L at room temperature. As it warms to body temperature, the volume expands proportionally. Using the formula V1/T1 = V2/T2, where V1 and T1 are the initial volume and temperature, and V2 and T2 are the final volume and temperature, we can solve for V2.

V1 = 0.6 L

T1 = 293 K

T2 = 310 K

0.6 L / 293 K = V2 / 310 K

Cross-multiplying and solving for V2, we get:

V2 = (0.6 L * 310 K) / 293 K

V2 = 0.636 L

Therefore, the volume of air when exhaled, after being warmed from room temperature to body temperature, is approximately 0.64 L.

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A) To find the position where the third sphere, C, experiences no net force, we can use the concept of electric forces and Coulomb's law. The net force on sphere C will be zero when the electric forces from sphere A and sphere B cancel each other out.

The formula for the electric force between two charges is given by [tex]F = \frac{{k \cdot |q_1 \cdot q_2|}}{{r^2}}[/tex],

where F is the force, k is the Coulomb's constant, q1 and q2 are the charges, and r is the distance between the charges.

Since sphere A has a positive charge and sphere B has a negative charge, the forces from both spheres will have opposite directions. To cancel out the forces, sphere C should be placed at a position where the distance and the magnitudes of the forces are balanced.

B) If the third sphere, C, had a charge of 16 C, the position where it should be placed to experience no net force will be different. The forces from sphere A and sphere B will now be different due to the change in charge. To determine the position, we can use the same approach as in part A, considering the new charge on sphere C.

Note: The specific calculations and coordinates for the positions of sphere C cannot be determined without additional information such as the values of the charges, the distances, and the Coulomb's constant.

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The ball reaches a maximum height of 289 feet after 4.25 seconds.

The height of a ball kicked upward can be modeled by the equation h = -16t^2 + vt + s, where h is the height in feet, t is the time in seconds, v is the initial velocity in feet per second, and s is the initial height in feet. In this case, the ball is kicked upward with an initial velocity of 68 feet per second.

To find the height of the ball at a given time, we can substitute the values into the equation. Let's assume the initial height, s, is 0 (meaning the ball is kicked from the ground).

Therefore, the equation becomes: h = -16t^2 + 68t + 0.

To find the maximum height, we need to determine the time it takes for the ball to reach its peak. At the peak, the velocity is 0.

To find this time, we set the equation equal to 0 and solve for t:

-16t^2 + 68t = 0.

Factoring out t, we get:

t(-16t + 68) = 0.

Setting each factor equal to 0, we find two solutions:

t = 0 (this is the initial time when the ball is kicked) and -16t + 68 = 0.

Solving -16t + 68 = 0, we find t = 4.25 seconds.

So, it takes 4.25 seconds for the ball to reach its peak height.

To find the maximum height, we substitute this time into the original equation:

h = -16(4.25)^2 + 68(4.25) + 0.

Evaluating this equation, we find the maximum height of the ball is 289 feet.

Therefore, the ball reaches a maximum height of 289 feet after 4.25 seconds.

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The subject of this question is Physics. It asks about the height of a ball kicked upward with an initial velocity of 68 feet per second. Projectile motion equations can be used to model the ball's height.

The subject of this question is Physics. The question is asking about the height of a ball that is kicked upward with an initial velocity of 68 feet per second. This can be modeled using equations of projectile motion.

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On a large spherical star with a gravitational acceleration of 25 miles per hour, an object thrown at a 30-degree angle with an initial velocity of 100 miles per hour will have a calculated horizontal displacement.

Resolve the initial velocity:

Given the initial velocity of the object is 100 miles per hour and it is launched at an angle of 30 degrees, we need to find its horizontal component. The horizontal component can be calculated using the formula: Vx = V * cos(θ), where V is the initial velocity and θ is the launch angle.

Vx = 100 * cos(30°) = 100 * √3/2 = 50√3 miles per hour.

Calculate the time of flight:

To determine the horizontal displacement, we first need to calculate the time it takes for the object to reach the ground. The time of flight can be determined using the formula: t = 2 * Vy / g, where Vy is the vertical component of the initial velocity and g is the gravitational acceleration.

Since the object is thrown vertically upwards, Vy = V * sin(θ) = 100 * sin(30°) = 100 * 1/2 = 50 miles per hour.

t = 2 * 50 / 25 = 4 hours.

Calculate the horizontal displacement:

With the time of flight determined, we can now find the horizontal displacement using the formula: Dx = Vx * t, where Dx is the horizontal displacement, Vx is the horizontal component of the initial velocity, and t is the time of flight.

Dx = 50√3 * 4 = 200√3 miles.

Therefore, the size of the displacement associated with the object in the horizontal direction, when thrown at an angle of 30 degrees and a speed of 100 miles per hour, on a large spherical star with a gravitational acceleration of 25 miles per hour, would be approximately 100 miles.

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The correct option for the following question is A. will expand forever. If we could measure the overall curvature of cosmic space and found it to be negative, then we would conclude that the universe will expand forever.

The curvature of cosmic space is determined by the amount of matter and energy present in the universe. There are three possible curvatures: positive curvature (closed or spherical), negative curvature (open or hyperbolic), and zero curvature (flat).

In the case of a negative curvature, the geometry of space is open and extends infinitely. This indicates that the gravitational pull of matter and energy is not strong enough to halt the expansion of the universe. Thus, the universe will continue to expand indefinitely. Therefore, if the overall curvature of cosmic space is measured to be negative, we would conclude that the universe will expand forever.

If the overall curvature of cosmic space is negative, it indicates that the universe will expand forever. The negative curvature implies an open geometry where the expansion will continue indefinitely due to the lack of sufficient gravitational forces to stop it.

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One way to keep the force between two particles constant while reducing their separation by a quarter is by increasing the mass of one particle while decreasing the mass of the other particle in the same proportion.

This adjustment in mass maintains the balance of gravitational forces and allows the force between the particles to remain constant.

According to the law of universal gravitation, the gravitational force between two particles is directly proportional to the product of their masses and inversely proportional to the square of their separation distance. If the separation distance is reduced by a quarter, the force between the particles would increase by a factor of four, assuming the masses remain the same.

To keep the force between the particles constant, the masses can be adjusted accordingly. One way to achieve this is by increasing the mass of one particle by a certain factor while decreasing the mass of the other particle by the same factor.

This adjustment ensures that the product of the masses remains the same, balancing out the increase in force caused by the reduced separation distance.

By carefully adjusting the masses, it is possible to maintain a constant gravitational force between the particles even when the separation distance changes.

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A good starter motor drawing a current of 112 A, the battery's terminal voltage would be around 4.944 V.

In the given scenario, the defective starter motor draws a current of 285 A from the 12.6 V battery, resulting in a voltage drop at the battery terminals to 7.33 V. On the other hand, a good starter motor should draw only 112 A.

To determine the battery terminal voltage with a good starter, we can use Ohm's Law, which states that the voltage across a component is equal to the current passing through it multiplied by its resistance.

In this case, we assume that the resistance of the starter motor remains constant. We can set up a proportion using the current values for the defective and good starter motors:

V = I R

285 A / 12.6 V = 112 A / x V

285 A * x V = 12.6 V * 112 A

x V = (12.6 V * 112 A) / 285 A

x V ≈ 4.944 V

Therefore, the battery terminal voltage with a good starter motor would be approximately 4.944 V.

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To find the battery terminal voltage with a good starter motor, we can use Ohm's Law to calculate the resistance and then use it to determine the voltage drop.

To find the battery terminal voltage with a good starter, we can use Ohm's Law, which states that voltage (V) is equal to current (I) multiplied by resistance (R). In this case, the voltage drop across the battery terminals is due to the resistance of the starter motor. We can calculate the resistance using the formula R = V/I. For the defective starter motor, the resistance would be 12.6 V / 285 A = 0.0442 ohm. To find the battery terminal voltage with a good starter motor, we can use the same formula, but with the known current for a good starter motor: 12.6 V / 112 A = 0.1125 ohm. Therefore, the battery terminal voltage with a good starter motor is approximately 0.1125 V.

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The angular deceleration of the gambling wheel is -0.785 rad/s².

The initial angular velocity, ω₀ = 1.5 rev/s

The final angular velocity, ω = 0

Time taken, t = 12 s

The relation between angular velocity, angular acceleration and angular displacement is given by

ω = ω₀ + αt

Also, angular displacement, θ = ω₀t + ½αt²

If the wheel comes to rest, ω = 0

The first equation becomes α = -ω₀/t = -1.5/12 = -0.125 rev/s²

The value of α is negative because it is deceleration and opposes the initial direction of motion of the wheel (i.e. clockwise).

To find the angular deceleration in radians per second per second, we can convert the angular acceleration from rev/s² to rad/s².

1 rev = 2π rad

Thus, 1 rev/s² = 2π rad/s²

Therefore, the angular deceleration is

α = -0.125 rev/s² × 2π rad/rev = -0.785 rad/s² (to three significant figures)

Hence, the angular deceleration of the gambling wheel is -0.785 rad/s².

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The current flowing through the wire is approximately 3531.97 A. The concept of magnetic forces between current-carrying wires. The force between two parallel conductors is given by the equation:

F = (μ₀ * I₁ * I₂ * L) / (2π * d),

where:

F is the force between the wires,

μ₀ is the permeability of free space (4π x 10^-7 Tm/A),

I₁ and I₂ are the currents in the wires,

L is the length of the wire,

d is the distance between the wires.

In this case, the force acting on the 20 cm wire is equal to its weight. Since it is floating with no tension in its suspension leads, the magnetic force must balance the gravitational force. Let's calculate the force due to gravity first.

Weight = mass * acceleration due to gravity

Weight = 0.016 kg * 9.81 m/s²

Weight = 0.15696 N

F = Weight

(μ₀ * I₁ * I₂ * L) / (2π * d) = Weight

μ₀ = 4π x 10^-7 Tm/A,

L = 0.2 m (20 cm),

d = 2 mm = 0.002 m,

Weight = 0.15696 N,

(4π x 10^-7 Tm/A) * I * (-I) * (0.2 m) / (2π * 0.002 m) = 0.15696 N

I² = (0.15696 N * 2 * 0.002 m) / (4π x 10^-7 Tm/A * 0.2 m)

I² = 0.15696 N * 0.01 / (4π x 10^-7 Tm/A)

I² = 0.015696 / (4π x 10^-7)

I² = 1.244 / 10^-7

I² = 1.244 x 10^7 A²

I = √(1.244 x 10^7 A²)

I ≈ 3531.97 A

Therefore, the current flowing through the wire is approximately 3531.97 A.

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The beat frequency that the car driver hears when the siren sound is reflected from the building can be calculated as the difference between the frequency of the emitted siren and the frequency of the reflected sound.

When the fire car emits the siren sound, the sound waves travel towards the building with a speed of vs. The frequency of the emitted siren is represented by f. Once the sound waves reach the building, they are reflected back towards the fire car. Since the car is moving towards the building, the speed of the car is effectively added to the speed of sound, resulting in a change in the frequency of the reflected sound.

The frequency of the reflected sound can be calculated using the Doppler effect equation for a moving source:

f' = (v + vs) / (v - vs) * f

where f' is the frequency of the reflected sound and v is the speed of sound.

The beat frequency is then obtained by subtracting the original frequency from the reflected frequency:

Beat frequency = f' - f

This represents the difference in frequency that the car driver hears due to the reflection of the sound waves from the building.

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When a ray of light in air strikes the surface of a glass block at an incident angle of 40°, the angle of refraction is approximately 23.63°.

To compute the angle of refraction, we can use Snell's law, which relates the angle of incidence (θ1) and angle of refraction (θ2) to the refractive indices of the two media.

Snell's law states:

n1 * sin(θ1) = n2 * sin(θ2), where n1 is the refractive index of the incident medium (air) and n2 is the refractive index of the glass block.

The incident angle (θ1) is 40° and the refractive index of the glass block (n2) is 1.56, and since the incident medium is air with a refractive index close to 1, we can rearrange Snell's law to solve for the angle of refraction (θ2).

Using the formula, sin(θ2) = (n1 * sin(θ1)) / n2,

we substitute the values:

sin(θ2) = (1 * sin(40°)) / 1.56.

Calculating sin(θ2) ≈ 0.4029, we can take the inverse sine to find θ2.

θ2 ≈ sin^(-1)(0.4029) ≈ 23.63°.

Therefore, the angle of refraction is approximately 23.63°.

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Explanation:

To find the number of oxygen molecules in a normal breath, we can use the ideal gas law equation, which relates the pressure, volume, temperature, and number of molecules of a gas:

PV = nRT

Where:

P = Pressure (in Pa)

V = Volume (in m³)

n = Number of moles

R = Ideal gas constant (8.314 J/(mol·K))

T = Temperature (in K)

First, let's calculate the number of moles of air inhaled during a normal breath:

V = 5.16 x 10^4 m³ (Volume of air inhaled)

P = 0.967 x 10^5 Pa (Pressure in the lungs)

R = 8.314 J/(mol·K) (Ideal gas constant)

T = 310 K (Temperature)

Rearranging the equation, we get:

n = PV / RT

n = (0.967 x 10^5 Pa) * (5.16 x 10^4 m³) / (8.314 J/(mol·K) * 310 K)

n ≈ 16.84 mol

Next, let's find the number of oxygen molecules inhaled. Since fresh air contains approximately 21% oxygen, we can multiply the number of moles by the fraction of oxygen in the air:

Number of oxygen molecules = n * (0.21)

Number of oxygen molecules ≈ 16.84 mol * 0.21

Number of oxygen molecules ≈ 3.54 mol

Finally, we'll convert the number of moles of oxygen molecules to the actual number of molecules by using Avogadro's number, which is approximately 6.022 x 10^23 molecules/mol:

Number of oxygen molecules = 3.54 mol * (6.022 x 10^23 molecules/mol)

Number of oxygen molecules ≈ 2.13 x 10^24 molecules

Therefore, in a normal breath, there are approximately 2.13 x 10^24 oxygen molecules.

The maximum speed of the photoelectrons is 1.355 × 10^6 m/s.

The formula for energy of a photon is given by,E = hf = hc/λ

where E is the energy of a photon, f is its frequency, h is Planck's constant, c is the speed of light, and λ is the wavelength. For this question,

h = 6.626 × 10^-34 J s and

c = 3.00 × 10^8 m/s .

Part A

The energy of each incident photon is 5.162×10−19 J

The power of the incident light is 0.74 W.

The total number of photons hitting the metal surface in 3.0 s is calculated as:

Energy of photons = Power × Time => Energy of 1 photon × Number of photons = Power × Time

So,

Number of photons = Power × Time/Energy of 1 photon

Therefore, Number of photons = 0.74 × 3.0 / 5.162 × 10^-19 = 4293.3 ≈ 4293.

Thus, 4293 photons in the incident light hit the metal surface in 3.0 s.

Part B

The energy required to remove an electron from the metal surface is known as the work function of the metal.

The work function W0 of the metal surface used is 2.71 eV = 2.71 × 1.6 × 10^-19 J = 4.336 × 10^-19 J.

Each photon must transfer at least the energy equivalent to the work function to the electron. The maximum kinetic energy of the photoelectrons is given by:

KE

max = Energy of photon - Work function KE

max = (5.162×10−19 J) - (2.71 × 1.6 × 10^-19 J) = 0.822 × 10^-18 J.

Thus, the max kinetic energy of the photoelectrons is 0.822 × 10^-18 J.

Part C

The maximum speed vmax of the photoelectrons is given by the classical physics formula for kinetic energy, which is:

KEmax = (1/2)mv^2

Where m is the mass of an electron, and v is the maximum speed of photoelectrons.The mass of an electron is 9.11×10−31 kg.

Thus, vmax = sqrt[(2 × KEmax) / m]`vmax = sqrt[(2 × 0.822 × 10^-18 J) / 9.11 × 10^-31 kg] = 1.355 × 10^6 m/s

Therefore, the maximum speed of the photoelectrons is 1.355 × 10^6 m/s.

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The magnitude of the net force applied to the mass is 45N when it is at maximum speed

To find the magnitude of the net force applied to the mass when it is at maximum speed, we need to consider the restoring force exerted by the spring.

In simple harmonic motion, the restoring force exerted by a spring is given by Hooke's law:

F = -kx

where F is the force, k is the spring constant, and x is the displacement from the equilibrium position.

In this case, the mass is attached to the spring and undergoes simple harmonic motion with an amplitude of 20 cm, which corresponds to a maximum displacement from the equilibrium position.

At maximum speed, the mass is at the extreme points of its motion, where the displacement is maximum. Therefore, the force applied by the spring is at its maximum as well.

Substituting the given values into Hooke's law:

F = -(225 N/m)(0.20 m) = -45 N

Since the force is a vector quantity and the question asks for the magnitude of the net force, the answer is:

Magnitude of the net force = |F| = |-45 N| = 45 N

Therefore, the correct option is (a) 45 N.

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charging by conduction involves the transfer of electrons through various means like proximity, contact, and grounding, resulting in objects acquiring charges.

Charging by conduction is a process that involves the transfer of electrons between objects. When a charged object is brought near an uncharged object, electrons in the uncharged object can shift due to the electrostatic force between the charges. This causes the electrons to redistribute, leading to an attraction between the two objects. Eventually, if the objects come into direct contact, electrons can move from the charged object to the uncharged object until both objects reach an equilibrium in terms of charge.

Another method of charging by conduction involves touching a charged object to an uncharged object and then grounding it. When the charged object is connected to the ground, electrons can flow from the charged object to the ground, effectively neutralizing the charge on the charged object. Simultaneously, the uncharged object gains electrons, acquiring a charge. This process allows the transfer of electrons from one object to another through the grounding connection.

Rubbing two objects together is a different charging method called charging by friction. In this case, when two objects are rubbed together, one material tends to gain electrons while the other loses electrons. The transfer of electrons during the rubbing process leads to one object becoming positively charged (having lost electrons) and the other becoming negatively charged (having gained electrons).

Therefore, charging by conduction involves the transfer of electrons through various means like proximity, contact, and grounding, resulting in objects acquiring charges.

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The frequency of the emitted gamma photons with an energy of 140 keV is incorrect.

Step 1:

The frequency of the emitted gamma photons with an energy of 140 keV is incorrectly calculated.

Step 2:

To calculate the frequency of the emitted gamma photons, we can use the equation E = hf, where E is the energy of the photon, h is Planck's constant, and f is the frequency of the photon. In this case, we are given the energy of the photon (140 keV) and need to find the frequency.

First, we need to convert the energy from keV to joules. Since 1 keV is equal to 1.6 × 10⁻¹⁶ J, the energy of the photon can be calculated as follows:

140 keV = 140 × 10³ × 1.6 × 10⁻¹⁶ J = 2.24 × 10⁻¹⁴ J

Now we can rearrange the equation E = hf to solve for the frequency f:

f = E / h = (2.24 × 10⁻¹⁴ J) / (6.6 × 10⁻³⁴ Js) ≈ 3.39 × 10¹⁹ Hz

Therefore, the correct frequency of the emitted gamma photons with an energy of 140 keV is approximately 3.39 × 10¹⁹ Hz.

Planck's constant, denoted by h, is a fundamental constant in quantum mechanics that relates the energy of a photon to its frequency. It quantifies the discrete nature of energy and is essential in understanding the behavior of particles at the microscopic level.

By applying the equation E = hf, where E is energy and f is frequency, we can determine the frequency of a photon given its energy. In this case, we used the energy of the gamma photons (140 keV) and Planck's constant to calculate the correct frequency. It is crucial to be accurate in the conversion of units to obtain the correct result.

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A. Wavelength λ = 1.453 * 10^8 / (4.107t - Bz)

B. E(z, t) = [0, 0, (0.133 / 4π × 10^-7)zcos(4.107t)]

Given the magnetic field equation for a plane wave traveling in free space, the task is to determine the wavelength λ and the corresponding electric field E(z, t) using the Ampere-Maxwell law in the time domain.

The magnetic field equation is:

H(z, t) = 0.133cos(4.107t - Bz)a (A/m)

To find the wavelength λ, we can use the relationship between wavelength, velocity, and frequency, given by:

λ = v / f

Since the wave is traveling in free space, its velocity (v) is equal to the speed of light:

v = 3 * 10^8 m/s

The frequency (f) can be obtained from the magnetic field equation:

ω = 4.107t - Bz

Also, ω = 2πf

Therefore:

4.107t - Bz = 2πf

Solving for f:

f = (4.107t - Bz) / (2π)

From this, we can calculate the wavelength as:

λ = v / f

λ = 3 * 10^8 / [(4.107t - Bz) / (2π)]

λ = 1.453 * 10^8 / (4.107t - Bz)

b) To determine the corresponding electric field E(z, t) using the Ampere-Maxwell law in the time domain, we start with the Ampere-Maxwell law:

∇ × E = - ∂B / ∂t

Using the provided magnetic field equation, B = μ0H, where μ0 is the permeability of free space, we can express ∂B / ∂t as ∂(μ0H) / ∂t. Substituting this into the Ampere-Maxwell law:

∇ × E = - μ0 ∂H / ∂t

Applying the curl operator to E, we have:

∇ × E = i(∂Ez / ∂y) - j(∂Ez / ∂x) + k(∂Ey / ∂x) - (∂Ex / ∂y)

Substituting this into the Ampere-Maxwell law and simplifying for a one-dimensional magnetic field equation, we get:

i(∂Ez / ∂y) - j(∂Ez / ∂x) = - μ0 ∂H / ∂t

The electric field component Ez can be obtained by integrating (∂H / ∂t) with respect to s:

Ez = (-1 / μ0) ∫(∂H / ∂t) ds

Substituting the magnetic field equation into this expression, we get:

Ez = (-1 / μ0) ∫(-B) ds

Ez = (B / μ0) s + constant

For this problem, we don't need the constant term. Therefore:

Ez = (B / μ0) s

By substituting the values for B and μ0 from the given magnetic field equation, we can express Ez as:

Ez = (0.133 / 4π × 10^-7)zcos(4.107t)

Thus, the corresponding electric field E(z, t) is given by:

E(z, t) = [0, 0, Ez]

E(z, t) = [0, 0, (0.133 / 4π × 10^-7)zcos(4.107t)]

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Force on a moving charge in a magnetic field is q( v × B ).Thus if the particle is moving along the magnetic field,  F=0.

Hence the particle continues to move along the incident direction, in a straight line.When the particle is moving perpendicular to the direction  of magnetic field, the force is perpendicular to both direction of velocity and the magnetic field.

Then the force tends to move the charged particle in a plane perpendicular to the direction of magnetic field, in a circle.

If the direction of velocity has both parallel and perpendicular components to the direction magnetic field, the perpendicular component tends to move it in a circle and parallel component tends to move it along the direction of magnetic field. Hence the trajectory is a helix.

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