A contact lens is made of plastic with an index of refraction of 1.60. The lens has an outer radius of curvature of 2.08 cm and an inner radius of curvature of 2.48 cm. What is the focal length of the lens?

Answer:

Question 4 is actually Acceleration

Answer:

a. Concave mirror, radius of curvature = 16 cm b. magnification = 2

Explanation:

a. Since the image is upright and larger than the object, we need a concave mirror.

We know image height, h'/object height, h = -image distance, d'/object distance, d

h'/h = -d'/d

Using the real is positive convention,

h'= + 5.4 cm, h = + 2.7 cm and d = + 12 cm.

So, + 5.4 cm/+ 2.7 cm = -d'/+ 12 cm

2 = -d'/12

d' = -2 × 12 cm

= -24 cm

Using the mirror formula 1/d + 1/d' = 2/r where r = radius of curvature of the mirror

1/+12 + 1/- 24 = 2/r

1/12(1 - 1/2) = 2/r

1/12(1/2) = 2/r

1/24 = 2/r

r/2 = 24

r = 2 × 24

r = 48 cm

b.

magnification = image height, h'/object height,h = + 5.4 cm/+ 2.7 cm = 2

Answer:

0 j

Explanation:

The work done by the employee on the box at the given zero displacement is 0 J.

The given parameters;

The work done by the employee on the box is calculated as follows;

W = Fd

where;

Since the employee sits on the box without moving it, the distance moved by the box = 0

W = 500 x 0

W = 0 J

Thus, the work done by the employee on the box is 0 J.

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Answer: All UV can have harmful effects on biological matter (such as causing cancers) with the highest energies causing the most damage.

Explanation:

Answer:

As tectonic plates slowly move away from each other, heat from the mantle's convection currents makes the crust more plastic and less dense.

Explanation:

Answer: The main cause of sea floor spreading are the directions and force of the moving tectonic plates.

Explanation:

Answer:

Yes it is matter

Explanation:

In physics, usually the word "electricity" isn't really used. "Electric current" is more common, and is defined as the flow of charges, where the charges are held by particles (electrons). Electrons have mass, so they are definitely matter.

Answer:

destructive interference occurs

Answer:

T = 10 s

Explanation:

First, we need to find the frequency of the object as follows:

[tex]Frequency = f = \frac{Speed\ in\ rpm}{60}[/tex]

where,

Speed = Angular Speed = 6 rpm

Therefore,

[tex]f = \frac{6\ rpm}{60}\\\\f = 0.1\ Hz[/tex]

Now, for time period (T):

[tex]Time\ Period = T = \frac{1}{f}\\\\T = \frac{1}{0.1\ Hz}\\\\[/tex]

T = 10 s

Answer:

The value is [tex]p = - 2.63 \ Diopters[/tex]

Explanation:

From the question we are told that  

      The value of the far point is  [tex]a = 40 \ cm = 0.4 \ m[/tex]

      The distance of the lens to the eye is  [tex]b = 2 \ cm = 0.02[/tex]

Generally

        [tex]1 Diopter = > 1 m^{-1}[/tex]

Generally the power spectacle lens needed is mathematically represented as

           [tex]p = \frac{1}{d_o } + \frac{1}{d_i}[/tex]

Here [tex]d_o[/tex] is the object distance which for a near sighted person is [tex]d_o = \infty[/tex]

And  [tex]d_i[/tex] is the image distance which is evaluated as

        [tex]d_i = b - a[/tex]

=>     [tex]d_i = 0.02 - 0.4[/tex]

=>     [tex]d_i = -0.38 \ m[/tex]

So

         [tex]p = \frac{1}{\infty } + \frac{1}{-0.38}[/tex]

=>      [tex]p = 0 - 2.63[/tex]

=>      [tex]p = - 2.63 \ Diopters[/tex]

Answer:

6sec and 8 postion

Explanation:

Explanation:

Single slit diffraction

Diffraction is the phenomenon of spreading out of waves as they pass through an aperture or around objects. Diffraction occurs when the size of the aperture or obstacle is of the same order of magnitude as the wavelength of the incident wave. For very small aperture sizes, the vast majority of the wave is blocked. in case of  large apertures the wave passes by or through the obstacle without any significant diffraction.

Answer:

a) [tex]F_{x} = 58.2 N[/tex]

[tex] F_{y} = 48.9 N [/tex]

b) a = 1.5 m/s²

Explanation:

a) The horizontal and vertical components of Emily's force can be found knowing the angle and the exerted force.

Since the handle is inclined at 40.0° below the horizontal we have:

[tex] F_{x} = |F|*cos(\theta) = 76.0 N*cos(40) = 58.2 N [/tex]

[tex] F_{y} = |F|*sin(\theta) = 76.0 N*sin(40) = 48.9 N [/tex]

b) The acceleration of the car can be calculated as follows:

[tex] F_{x} = ma [/tex]        

We used the horizontal component of the force because the cart is moving in that direction.

[tex] a = \frac{F_{x}}{m} = \frac{58.2 N}{38.8 kg} = 1.5 m/s^{2} [/tex]

Hence, the acceleration of the car is 1.5 m/s².    

I hope it helps you!

Answer:

The correct answer is 4R1

Explanation:

According to the given scenario ,the radius of the tightest curve on the same road without skidding is as follows:

As we know that

Centeripetal Acceleration is

= v^2 ÷ r

In the case when velocity becomes 2 times so the r would be 4 times

So, the radius of the  tightest curve on the same road without skidding is 4R1

Answer:

i believe that they are or there's something out there

Explanation:

:)

Given that,

Mass of student 1, m₁ = 90 kg

Mass of student 2, m₂ = 60 kg

Speed of student 1, v₁ = 5 m/s

To find,

The velocity of the other student.

Solution,

Using the conservation of momentum to find the velocity of the other student. Let it is v₂.

[tex]m_1v_1=m_2v_2\\\\v_2=\dfrac{m_1v_1}{m_2}\\\\v_2=\dfrac{90\times 5}{60}\\\\=7.5\ m/s[/tex]

So, the velocity of the other student is 7.5 m/s.

Given that,

The rate of change of current = 3.2 A/s

Emf induced in the coil = 5.7 V

To find,

The magnitude of the mutual inductance of the two coils.

Solution,

The mutual inductance between the coils is given by the formula as follows :

[tex]\epsilon=M\dfrac{dI}{dt}\\\\M=\dfrac{\epsilon}{\dfrac{dI}{dt}}\\\\M=\dfrac{5.7}{3.2}\\\\=1.78\ H[/tex]

So, the mutual inductance of the two coils is 1.78 H.

Answer:

The heat absorbed in each cycle is 9,234.286 J

Explanation:

Given;

power output, P = 5 kW = 5,000 W

efficiency of the engine, e = 30 % = 0.3

thermal heat expelled, [tex]Q_c[/tex] = 6464 J

let the heat absorbed = [tex]Q_h[/tex]

The efficiency of the engine is given as;

[tex]e = \frac{W}{Q_h} = \frac{Q_h-Q_c}{Q_h} = \frac{Q_h}{Q_h} - \frac{Q_c}{Q_h} = 1-\frac{Q_c}{Q_h}\\\\e = 1-\frac{Q_c}{Q_h}\\\\0.3 = 1-\frac{Q_c}{Q_h}\\\\\frac{Q_c}{Q_h} = 1-0.3\\\\\frac{Q_c}{Q_h} = 0.7\\\\Q_h = \frac{Q_c}{0.7} \\\\Q_h = \frac{6464}{0.7} = 9,234.286 \ J.[/tex]

Therefore, the heat absorbed in each cycle is 9,234.286 J.

Answer:

So we can have energy  for electronics. It limits the flow of electric current

Explanation:

It’s in the answer!

Answer:

Basically, the function of a resistor is always to oppose the flow of current through it and the strength of this opposition is termed as its resistance.

An electric current causes the magnetic field around the wire. The correct answer is A.

The magnetic field around a wire is caused by the flow of electric current through the wire. When an electric current passes through a wire, it generates a magnetic field that forms circular lines of magnetic flux around the wire. This phenomenon is described by Ampere's law, which states that a magnetic field is produced by an electric current and its strength is directly proportional to the magnitude of the current.

The relationship between the electric current and the magnetic field can be understood using the right-hand rule. If you wrap your right hand around the wire with your thumb pointing in the direction of the current, the curled fingers indicate the direction of the magnetic field lines.

Therefore, an electric field is generated by an electric charge, not by an electric current. While an electric field can exist around a wire if there is a potential difference (voltage) applied across it, it is the flow of electric current that primarily generates the magnetic field.

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#SPJ1

a = v² / R = (2 m/s)² / (0.1 m) = 40 m/s²

Answer:

The total momentum is zero.

Explanation:

This problem can be solved by applying the momentum conservation theorem and the amount of motion. This theorem tells us that the amount of motion is conserved before and after a collision.

In the next equation, we will write to the left of the equal sign the amount of motion before the collision and to the right the amount of motion after the collision.

[tex](P_{1})-(P_{2})=P_{3}[/tex]

where:

P₁ = momentum of the ball moving to the right, before the collision = 85 [kg*m/s]

P₂ = momentum of the ball moving to the left, before the collision = - 85 [kg*m/s]

P₃ = Final momentum after the collision [kg*m/s]

[tex](85) - 85 = P_{3}\\P_{3}= 0[/tex]

There is no movement of any of the balls, they remain at rest after the impact.

Answer:

Maximum=70 m

Minimum=26 m

Explanation:

Vector Addition

Since vectors have magnitude and direction, adding them takes into consideration not only the magnitudes but also their respective directions. Two vectors can be totally collaborative, i.e., point to the same direction, or be totally opposite. In the first case, the magnitude of the sum is at maximum. Otherwise, it's at a minimum.

Thus, the maximum magnitude of the sum is 48+22 = 70 m and the minimum magnitude of the sum is 48-22= 26 m

Answer:

[tex]t = 0.55[/tex]

Explanation:

Given

[tex]Height, s = 1.5m[/tex]

[tex]Velocity, v = 70m/s[/tex]

Required

Determine the time to hit the ground

Using free fall formula:

[tex]S = \frac{1}{2}gt^2[/tex]

Take g as 9.8 and substitute value for S

[tex]1.5 = \frac{1}{2} * 9.8 * t^2[/tex]

[tex]1.5 = 4.9 * t^2[/tex]

Make t^2 the subject

[tex]t^2 = \frac{1.5}{4.9}[/tex]

[tex]t^2 = 0.30612244898[/tex]

Solve for t

[tex]t = \sqrt{0.30612244898[/tex]

[tex]t = 0.55[/tex] -- approximated

Answer:

W = - 118.24 J (negative sign shows that work is done on piston)

Explanation:

First, we find the change in internal energy of the diatomic gas by using the following formula:

[tex]\Delta\ U = nC_{v}\Delta\ T[/tex]

where,

ΔU = Change in internal energy of gas = ?

n = no. of moles of gas = 0.0884 mole

Cv = Molar Specific Heat at constant volume = 5R/2 (for diatomic gases)

Cv = 5(8.314 J/mol.K)/2 = 20.785 J/mol.K

ΔT = Rise in Temperature = 18.8 K

Therefore,

[tex]\Delta\ U = (0.0884\ moles)(20.785\ J/mol.K)(18.8\ K)\\\Delta\ U = 34.54\ J[/tex]

Now, we can apply First Law of Thermodynamics as follows:

[tex]\Delta\ Q = \Delta\ U + W[/tex]

where,

ΔQ = Heat flow = - 83.7 J (negative sign due to outflow)

W = Work done = ?

Therefore,

[tex]-83.7\ J = 34.54\ J + W\\W = -83.7\ J - 34.54\ J\\[/tex]

W = - 118.24 J (negative sign shows that work is done on piston)

Answer:

-49.2

Explanation:

Trust me bro

Given that,

At 3.00 m from a source that is emitting sound uniformly in all directions, the sound level is 60.0 dB.

To find,

The distance from the source would the sound level be one-fourth the sound level at 3.00 m.

Solution,

The intensity from a source is inversely proportional to the distance.

Let I₁ = 60 dB, r₁ = 3 m, I₂ = 60/4 = 15 dB, r₂ =?

Using relation :

[tex]\dfrac{I_1}{I_2}=\dfrac{r_2^2}{r_1^2}\\\\r_2^2=\dfrac{I_1r_1^2}{I_2}\\\\r_2^2=\dfrac{60\times (3)^2}{15}\\\\r_2=6\ m[/tex]

So, at a distance of 6 m the sound level will be one fourth of the sound level at 3 m.

Answer: c. 1.89 x 10^14 J

Explanation:

By Einstein's equation, we know that:

E = m*c^2

Where m is the mass-consumed in this case:

m = 2.10g

And we must rewrite this in Kg, knowing that:

1kg = 1000g

Then:

m = 2.10g = (2.10/1000) kg = 0.0021 kg

And c is the speed of light:

c = 3*10^8 m/s.

Then the energy will be:

E = 0.0021 kg*(3*10^8 m/s)^2 = 1.89*10^14 Joules.

The correct option is:

c. 1.89 x 10^14J

Answer: D

Explanation:

Answer:

The number of crate to be lifted is 27

Explanation:

Given;

mass of the crates, m = 25 kg

height in which the crate is lifted, h = 1.0 m

power output, P = 110 W

time to complete the task, t = 1 minutes = 60 s

The input energy is equal to the gravitational energy due to height the crate is lifted is given as;

E(input) = mgh

E(input)  = 25 x 9.8 x 1

E(input)  = 245 J

Output energy is given as;

E(output) = P x t

E(output) = 110 x 60

E(output) = 6600 J

Let the number of crate to be lifted = n

n x E(input)  = E(output)

n x 245 = 6600

n = 6600 / 245

n = 27 crates

Answer:

I think the answer is  

a "cookbook" recipe for performing scientific investigations

Explanation: