Please help! Average speed. Show work!

Please Help! Average Speed. Show Work!

Answers

Answer 1

Answer:

3.78 m/s

Explanation:

Recall that the formula for average speed is given by

Speed = Distance ÷ Time taken

Where,

Speed = we are asked to find this

Distance = given as 340m

Time taken = 1.5 min = 1.5 x 60 = 90 seconds

Substituting the values into the equation:

Speed = Distance ÷ Time taken

= 340 meters  ÷ 90 seconds

= 3.777777 m/s

= 3.78 m/s (round to nearest hundredth)

Answer 2

Answer:

3.78 m/s

Option D is the right option.

solution,

Distance travelled=340 metre

Time taken= 1.5 minutes ( 1 minute=60 seconds)

=1.5* 60

=90 seconds

Now,

Average speed:

[tex] \ \frac{distance \: travelled \: }{time \: taken} \\ = \frac{340 \: m}{90 \: s} \\ = 3.78 \: metre \: per \: second[/tex]

Hope this helps...

Good luck on your assignment..


Related Questions

g A point mass of 1.5kg is attached to a spring and set to oscillate through simple harmonic oscillations. If the period of the oscillation is 10s, find the spring constant.

Answers

Answer:

k = 0.6 N/m

Explanation:

The time period of a spring mass oscillation system is given by the following formula:

T = 2π√(m/k)

where,

T = Time Period of Oscillation = 10 s

m = Mass attached to the spring = 1.5 kg

k = spring constant = ?

Therefore,

10 s = 2π√(1.5 kg/k)

squaring on both sides we get:

100 s² = 4π²(1.5 kg/k)

k = 6π² kg/100 s²

k = 0.6 N/m

How would the magnetic field lines appear for a bar magnet cut at the midpoint, with the two pieces placed end to end with a space in between such that the cut edges are closest to each other? What would the general shape of the field lines look like? What would the field lines look like in between the two pieces?

Answers

Answer:

Explanation:

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hich muscle fibers are best suited for activities that involve lifting large, heavy objects for a short period of time? cardiac slow twitch intermediate fast twitch

Answers

Answer:

Dead lifting uses tho muscle fundamentals

Explanation:

Answer:

Fast twitch

Explanation:

Edmentum

A block attached to a spring undergoes simple harmonic motion on a horizontal frictionless surface. Its total energy is 50 J. When the displacement is half the amplitude, the kinetic energy is

Answers

Answer:

The kinetic energy at a displacement of half the amplitude is 37.5 J

Explanation:

Given;

total energy on the spring, E = 50 J

When the displacement is half the amplitude, the total energy in the spring is sum of the kinetic energy and elastic potential energy.

E = K + U

Where;

K is the kinetic energy

U is the elastic potential energy

K = E - U

K = E - ¹/₂KA²

When the displacement is half = ¹/₂(A) = A/₂

K = E - ¹/₂K(A/₂)²

K = E - ¹/₂K(A²/₄)

K = E - ¹₄(¹/₂KA²)

Recall, E = ¹/₂KA²

K = ¹/₂KA² - ¹₄(¹/₂KA²)     (recall from simple arithmetic, 1 - ¹/₄ = ³/₄)

K = 1(¹/₂KA²) - ¹₄(¹/₂KA²)  = ³/₄(¹/₂KA²)

K = ³/₄(¹/₂KA²)

But E = ¹/₂KA² = 50J

K = ³/₄ (50J)

K = 37.5 J

Therefore, the kinetic energy at a displacement of half the amplitude is 37.5 J

The kinetic energy when the displacement is half the amplitude

Given the following data:

Total energy = 50 Joules.Displacement, x = [tex]\frac{A}{2}[/tex]

To find the kinetic energy when the displacement is half the amplitude:

The total energy of the system of a block and a spring is the sum of the spring's elastic potential energy and kinetic energy of the block and it's proportional to the square of the amplitude.

Mathematically, the total energy of the system of a block and a spring is given by the formula:

[tex]T.E = U + K.E[/tex]   .....equation 1.

[tex]T.E = \frac{1}{2} kA^2[/tex]

Where:

T.E is the total energy.U is the elastic potential energy.K.E is the kinetic energy.A is the amplitude.

Making K.E the subject of formula, we have:

[tex]K.E = T.E - U[/tex]   .....equation 2.

But, [tex]U = \frac{1}{2} kx^2[/tex]    ....equation 3.

Where:

k is spring constant.x is change in position (displacement).

Substituting the eqn 3 into eqn 2, we have:

[tex]K.E = T.E - \frac{1}{2} kx^2[/tex]

[tex]K.E = T.E - \frac{1}{2} k(\frac{A}{2})^2\\\\K.E = T.E - \frac{1}{2} k(\frac{A^2}{4})\\\\K.E = T.E - \frac{1}{4} (\frac{1}{2} kA^2)\\\\K.E = T.E - \frac{1}{4} (T.E)\\\\K.E = 50 - \frac{1}{4} (50)\\\\K.E = 50 - 12.5[/tex]

K.E = 37.5 Joules.

Read more: https://brainly.com/question/23153766

A 1.53-kg piece of iron is hung by a vertical ideal spring. When perturbed slightly, the system is moves up and down in simple harmonic oscillations with a frequency of 1.95 Hz and an amplitude of 7.50 cm. If we choose the total potential energy (elastic and gravitational) to be zero at the equilibrium position of the hanging iron, what is the total mechanical energy of the system

Answers

Answer:

E = 0.645J

Explanation:

In order to calculate the total mechanical energy of the system, you take into account that if the zero of energy is at the equilibrium position, then the total mechanical energy is only the elastic potential energy of the spring.

You use the following formula:

[tex]E=U_e=\frac{1}{2}kA^2[/tex]         (1)

k: spring constant = ?

A: amplitude of the oscillation = 7.50cm = 0.075m

The spring constant is given by:

[tex]f=\frac{1}{2\pi}\sqrt{\frac{k}{m}}[/tex]

[tex]k=4\pi^2f^2m[/tex]         (2)

f: frequency of the oscillation = 1.95Hz

m: mass of the piece of iron = 1.53kg

You replace the expression (1) into the equation (2) and replace the values of all parameters:

[tex]E=\frac{1}{2}(4\pi^2f^2m)A^2=2\pi^2f^2mA^2\\\\E=2\pi^2(1.95Hz)^2(1.53kg)(0.075m)^2=0.645J[/tex]

The totoal mechanical energy of the system is 0.645J

Two 60.o-g arrows are fired in quick succession with an initial speed of 82.0 m/s. The first arrow makes an initial angle of 24.0° above the horizontal, and the second arrow is fired straight upward. Assume an isolated system and choose the reference configuration at the initial position of the arrows.
(a) what is the maximum height of each of the arrows?
(b) What is the total mechanical energy of the arrow-Earth system for each of the arrows at their maximum height?

Answers

Answer:

a) The first arrow reaches a maximum height of 56.712 meters, whereas second arrow reaches a maximum height of 342.816 meters, b) Both arrows have a total mechanical energy at their maximum height of 201.720 joules.

Explanation:

a) The first arrow is launch in a parabolic way, that is, horizontal speed remains constant and vertical speed changes due to the effects of gravity. On the other hand, the second is launched vertically, which means that velocity is totally influenced by gravity. Let choose the ground as the reference height for each arrow. Each arrow can be modelled as particles and by means of the Principle of Energy Conservation:

First arrow

[tex]U_{g,1} + K_{x,1} + K_{y,1} = U_{g,2} + K_{x,2} + K_{y,2}[/tex]

Where:

[tex]U_{g,1}[/tex], [tex]U_{g,2}[/tex] - Initial and final gravitational potential energy, measured in joules.

[tex]K_{x,1}[/tex], [tex]K_{x,2}[/tex] - Initial and final horizontal translational kinetic energy, measured in joules.

[tex]K_{y,1}[/tex], [tex]K_{y,2}[/tex] - Initial and final vertical translational kinetic energy, measured in joules.

Now, the system is expanded and simplified:

[tex]m \cdot g \cdot (y_{2} - y_{1}) + \frac{1}{2}\cdot m \cdot (v_{y, 2}^{2} -v_{y, 1}^{2}) = 0[/tex]

[tex]g \cdot (y_{2}-y_{1}) = \frac{1}{2}\cdot (v_{y,1}^{2}-v_{y,2}^{2})[/tex]

[tex]y_{2}-y_{1} = \frac{1}{2}\cdot \frac{v_{y,1}^{2}-v_{y,2}^{2}}{g}[/tex]

Where:

[tex]y_{1}[/tex]. [tex]y_{2}[/tex] - Initial and final height of the arrow, measured in meters.

[tex]v_{y,1}[/tex], [tex]v_{y,2}[/tex] - Initial and final vertical speed of the arrow, measured in meters.

[tex]g[/tex] - Gravitational acceleration, measured in meters per square second.

The initial vertical speed of the arrow is:

[tex]v_{y,1} = v_{1}\cdot \sin \theta[/tex]

Where:

[tex]v_{1}[/tex] - Magnitude of the initial velocity, measured in meters per second.

[tex]\theta[/tex] - Initial angle, measured in sexagesimal degrees.

If [tex]v_{1} = 82\,\frac{m}{s}[/tex] and [tex]\theta = 24^{\circ}[/tex], the initial vertical speed is:

[tex]v_{y,1} = \left(82\,\frac{m}{s} \right)\cdot \sin 24^{\circ}[/tex]

[tex]v_{y,1} \approx 33.352\,\frac{m}{s}[/tex]

If [tex]g = 9.807\,\frac{m}{s^{2}}[/tex], [tex]v_{y,1} \approx 33.352\,\frac{m}{s}[/tex] and [tex]v_{y,2} = 0\,\frac{m}{s}[/tex], the maximum height of the first arrow is:

[tex]y_{2} - y_{1} = \frac{1}{2}\cdot \frac{\left(33.352\,\frac{m}{s} \right)^{2}-\left(0\,\frac{m}{s} \right)^{2}}{9.807\,\frac{m}{s^{2}} }[/tex]

[tex]y_{2} - y_{1} = 56.712\,m[/tex]

Second arrow

[tex]U_{g,1} + K_{y,1} = U_{g,3} + K_{y,3}[/tex]

Where:

[tex]U_{g,1}[/tex], [tex]U_{g,3}[/tex] - Initial and final gravitational potential energy, measured in joules.

[tex]K_{y,1}[/tex], [tex]K_{y,3}[/tex] - Initial and final vertical translational kinetic energy, measured in joules.

[tex]m \cdot g \cdot (y_{3} - y_{1}) + \frac{1}{2}\cdot m \cdot (v_{y, 3}^{2} -v_{y, 1}^{2}) = 0[/tex]

[tex]g \cdot (y_{3}-y_{1}) = \frac{1}{2}\cdot (v_{y,1}^{2}-v_{y,3}^{2})[/tex]

[tex]y_{3}-y_{1} = \frac{1}{2}\cdot \frac{v_{y,1}^{2}-v_{y,3}^{2}}{g}[/tex]

If [tex]g = 9.807\,\frac{m}{s^{2}}[/tex], [tex]v_{y,1} = 82\,\frac{m}{s}[/tex] and [tex]v_{y,3} = 0\,\frac{m}{s}[/tex], the maximum height of the first arrow is:

[tex]y_{3} - y_{1} = \frac{1}{2}\cdot \frac{\left(82\,\frac{m}{s} \right)^{2}-\left(0\,\frac{m}{s} \right)^{2}}{9.807\,\frac{m}{s^{2}} }[/tex]

[tex]y_{3} - y_{1} = 342.816\,m[/tex]

The first arrow reaches a maximum height of 56.712 meters, whereas second arrow reaches a maximum height of 342.816 meters.

b) The total energy of each system is determined hereafter:

First arrow

The total mechanical energy at maximum height is equal to the sum of the potential gravitational energy and horizontal translational kinetic energy. That is to say:

[tex]E = U + K_{x}[/tex]

The expression is now expanded:

[tex]E = m\cdot g \cdot y_{max} + \frac{1}{2}\cdot m \cdot v_{x}^{2}[/tex]

Where [tex]v_{x}[/tex] is the horizontal speed of the arrow, measured in meters per second.

[tex]v_{x} = v_{1}\cdot \cos \theta[/tex]

If [tex]v_{1} = 82\,\frac{m}{s}[/tex] and [tex]\theta = 24^{\circ}[/tex], the horizontal speed is:

[tex]v_{x} = \left(82\,\frac{m}{s} \right)\cdot \cos 24^{\circ}[/tex]

[tex]v_{x} \approx 74.911\,\frac{m}{s}[/tex]

If [tex]m = 0.06\,kg[/tex], [tex]g = 9.807\,\frac{m}{s^{2}}[/tex], [tex]y_{max} = 56.712\,m[/tex] and [tex]v_{x} \approx 74.911\,\frac{m}{s}[/tex], the total mechanical energy is:

[tex]E = (0.06\,kg)\cdot \left(9.807\,\frac{m}{s^{2}} \right)\cdot (56.712\,m)+\frac{1}{2}\cdot (0.06\,kg)\cdot \left(74.911\,\frac{m}{s} \right)^{2}[/tex]

[tex]E = 201.720\,J[/tex]

Second arrow:

The total mechanical energy is equal to the potential gravitational energy. That is:

[tex]E = m\cdot g \cdot y_{max}[/tex]

[tex]m = 0.06\,kg[/tex], [tex]g = 9.807\,\frac{m}{s^{2}}[/tex] and [tex]y_{max} = 342.816\,m[/tex]

[tex]E = (0.06\,kg)\cdot \left(9.807\,\frac{m}{s^{2}} \right)\cdot (342.816\,m)[/tex]

[tex]E = 201.720\,J[/tex]

Both arrows have a total mechanical energy at their maximum height of 201.720 joules.

A particle with a charge of 5 × 10–6 C and a mass of 20 g moves uniformly with a speed of 7 m/s in a circular orbit around a stationary particle with a charge of –5 × 10–6 C. The radius of the orbit is:

Answers

Answer:

r = 0.22m

Explanation:

To find the radius of the circular trajectory, you first take into account that the centripetal force of the charged particle, is equal to the electric force between the particle that is moving and the particle at the center of the orbit.

Then, you have:

[tex]F_c=F_e=ma_c[/tex]      (1)

m: mass of the particle = 20g = 20*10-3 kg

ac: centripetal acceleration = ?

q: charge of the particle = 5*10^-6C

Fe: electric force between the charges

The electric force is given by:

[tex]F_e=k\frac{qq'}{r^2}[/tex]             (2)

r: radius of the orbit

q': charge of the particle at the center of the orbit = -5*10^-6C

Furthermore, the centripetal acceleration is:

[tex]a_c=\frac{v^2}{r}[/tex]                 (3)

v: speed of the particle = 7m/s

You replace the expressions (2) and (3) in the equation (1) and solve for r:

[tex]k\frac{qq'}{r^2}=m\frac{v^2}{r}\\\\r=\frac{kqq'}{mv^2}[/tex]

Finally, you replace the values of all parameters in the previous expression:

[tex]r=\frac{(8.98*10^9Nm^2/C^2)(5*10^{-6}C)(5*10^{-6}C)}{(20*10^{-3}kg)(7m/s)^2}\\\\r=0.22m[/tex]

The radius of the circular trajectory is 0.22m

A tube of water is open on one end to the environment while the other end is closed. The height of the water relative to the base is 100 cm on the open end and 40 cm on the closed end. What is the absolute pressure of the water at the top of the closed end in units of atm

Answers

Answer:

1.06 atm

Explanation:

On the open end of the tube, the pressure will be the sum of atmospheric pressure and the pressure due to the height of water

The pressure due to a height of water = ρgh

where ρ is the density of water = 1000 kg/m^3

g is the acceleration due to gravity = 9.81 m/s^2

h is the height of the water column

The height of water column on the open end = 100 cm = 1 m

pressure on this end = ρgh = 1000 x 9.81 x 1 = 9810 Pa

Atmospheric pressure = 101325 Pa

The total pressure on the open end =  101325 Pa + 9810 Pa = 111135 Pa

The pressure due to the water column on the closed end = ρgh

The height of the water in the closed end = 40 cm = 0.4 m

The pressure due to this column of water = 1000 x 9.81 x 0.4 = 3924 Pa

The resultant pressure on the water on the top of the closed end of the tube = 111135 Pa - 3924 Pa = 107211 Pa

In atm unit, this pressure = 107211/101325 = 1.06 atm

a playground merry-go-round of radius r = 2.20 m has a moment of inertia i = 245 kg · m2 and is rotating at 11.0 rev/min about a frictionless vertical axle. facing the axle, a 26.0-kg child hops onto the merry-go-round and manages to sit down on the edge. what is the new angular speed of the merry-go-round?

Answers

Answer:

8.92 rpm

Explanation:

Given that

Radius of the merry go round, r = 2.2 m

Initial moment of inertia, I1 = 245 kgm²

Initial speed of rotation, w1 = 11 rpm

Mass of the child, m = 26 kg

To solve the problem, we use the law conservation of momentum

I1w1 = I2w2

I2 = mr² + I1

I2 = 245 + 26 * 2.2

I2 = 245 + 57.2

I2 = 302.2 kgm²

Now, applying the formula, we have

I1w1 = I2w2

245 * 11 = 302.2 * w2

w2 = 2695 / 302.2

w2 = 8.92 rpm

Thus, the new angular speed of the merry go round is 8.92 rpm

Which statement describes a disadvantage of using natural gas as an energy source? It is expensive to use. It is hard to stop using. It is a renewable resource. It is scarce in some parts of the world.

Answers

Answer:

B : It is hard to stop using.

Explanation:

just took the quiz ! hope this helps with anyone who needs it !

Due to the dependency on natural gas as a fuel, it is hard to stop using.

What is natural gas?

Natural gas is a fossil fuel which is obtained from the ground in association with petroleum.

Natural gas consists mainly of petroleum.

It is a non-renewable energy source.

Natural gas use contributes to global warming

However, due to the dependency on natural gas as a fuel, it is hard to stop using.

Learn more about natural gas at: https://brainly.com/question/815922

A ball bouncing against the ground and rebounding is an example of an elastic collision. Describe two different methods of evaluating this interaction, one for which momentum is conserved, and one for which momentum is not conserved. Explain your answer.

Answers

Answer:

Momentum is conserved when there are no outside forced present and it has an equal and opposite reaction, also momentum is conserved the ball's momentum is transferred to the ground. This first instance is the case of a Closed system.

The second case where momentum is not conserved is when there is a variation or difference in the moment of the ball because of influence of external forces

Find the average value of position x, momentump, and square of the mometum p2 for the ground and first excited states of the particle-in-a-box with mass m and box length L.

Answers

Answer:

Explanation:

Find the average value of position x, momentump, and square of the mometum p2 for the ground and first excited states of the particle-in-a-box with mass m and box length L.

A ball is thrown horizontally from the top of a 41 m vertical cliff and lands 112 m from the base of the cliff. How fast is the ball thrown horizontally from the top of the cliff?

Answers

Answer:

4.78 second

Explanation:

given data

vertical cliff = 41 m

height = 112 m

solution

we know here time taken to fall vertically from the cliff =  time taken to move horizontally   ..........................1

so we use here vertical component of ball

and that is accelerated motion with initial velocity = 0

so we can solve for it as

height = 0.5 ×  g ×  t²     ........................2

put here value

112 = 0.5 ×  9.8 ×  t²    

solve it we get

t²   = 22.857

t = 4.78 second

ball thrown horizontally from the top of the cliff in 4.78 second

If the velocity of a pitched ball has a magnitude of 47.0 m/s and the batted ball's velocity is 55.0 m/s in the opposite direction, find the magnitude of the change in momentum of the ball and of the impulse applied to it by the bat.

Answers

Answer:

14.79 kgm/s

Explanation:

Data provided in the question

Let us assume the mass of baseball =  m = 0.145 kg

The Initial velocity of pitched ball = [tex]v_i[/tex] = 47 m/s

Final velocity of batted ball in the opposite direction = [tex]v_f[/tex]= -55m/s

Based on the above information, the change in momentum is

[tex]\Delta P = m(v_f -v_i)[/tex]

[tex]= 0.145 kg(-55m/s - 47m/s)[/tex]    

= 14.79 kgm/s

Hence, the magnitude of the change in momentum of the ball is 14.79 kg m/s

Which of the following is not a benefit of improved cardiorespiratory fitness

Answers

Answer:

C - Arteries grow smaller

Explanation:

The option choices are:

A. Faster post-exercise recovery time

B. Lungs expand more easily

C. Arteries grow smaller

D. Diaphragm grows stronger

Explanation:

There are many advantages of cardiorespiratory fitness. It can decrease the risk of heart disease, lung cancer, type 2 diabetes, stroke, and other diseases. Cardiorespiratory health helps develop lung and heart conditions and enhances feelings of well-being.

A 0.140-kg baseball is thrown with a velocity of 27.1 m/sIt is struck by the bat with an average force of 5000 N, which results in a velocity of 37.0 m/s in the opposite direction from the original velocity. How long were the bat and ball in contact?

Answers

Answer:

The bat and the ball were in contact for 1.8 x 10⁻³ s

Explanation:

Given;

mass of baseball, m = 0.14 kg

initial velocity of the baseball, u = 27.1 m/s

applied force in opposite direction, F = -5000 N

final velocity in opposite direction, v = -37 m/s

Note: The applied force and final velocity are negative because they act in opposite direction to the initial velocity.

impulse received by the body = change in momentum of the  body

Ft = Δmv

Ft = mv - mu

Ft = m(v-u)

t = m(v-u) / F

[tex]t = \frac{0.14(-37-27.1)}{-5000} \\\\t = \frac{0.14(-64.1)}{-5000} \\\\t = \frac{-8.974}{-5000} \\\\t = 0.0018 \ s\\\\t = 1.8*10^{-3} \ s[/tex]

Therefore, the bat and the ball were in contact for 1.8 x 10⁻³ s

There was a major collision of an asteroid with the Moon in medieval times. It was described by monks at Canterbury Cathedral in England as a red glow on and around the Moon. How long (in s) after the asteroid hit the Moon, which is 3.77 ✕ 105 km away, would the light first arrive on Earth?

Answers

Answer:

Explanation:

speed of light = 3 x 10⁸ m /s .

distance between moon and the earth = 3.77 x 10⁵  x 10³m .

Time taken by light to cover the distance

= distance / speed

= 3.77 x 10⁸ / 3 x 10⁸

= 1.256  s

An archer shoots an arrow toward a 300-g target that is sliding in her direction at a speed of 2.10 m/s on a smooth, slippery surface. The 22.5-g arrow is shot with a speed of 37.5 m/s and passes through the target, which is stopped by the impact. What is the speed of the arrow after passing through the target

Answers

Answer:

The speed of the arrow after passing through the target is 30.1 meters per second.

Explanation:

The situation can be modelled by means of the Principle of Linear Momentum, let suppose that the arrow and the target are moving on the same axis, where the velocity of the first one is parallel to the velocity of the second one. The Linear Momentum model is presented below:

[tex]m_{a}\cdot v_{a,o} + m_{t}\cdot v_{t,o} = m_{a}\cdot v_{a,f} + m_{t}\cdot v_{t,f}[/tex]

Where:

[tex]m_{a}[/tex], [tex]m_{t}[/tex] - Masses of arrow and target, measured in kilograms.

[tex]v_{a,o}[/tex], [tex]v_{a,f}[/tex] - Initial and final speeds of the arrow, measured in meters per second.

[tex]v_{t,o}[/tex], [tex]v_{t,f}[/tex] - Initial and final speeds of the target, measured in meters per second.

The final speed of the arrow is now cleared:

[tex]m_{a} \cdot v_{a,f} = m_{a} \cdot v_{a,o} + m_{t}\cdot (v_{t,o}-v_{t,f})[/tex]

[tex]v_{a,f} = v_{a,o} + \frac{m_{t}}{m_{a}} \cdot (v_{t,o}-v_{t,f})[/tex]

If [tex]v_{a,o} = 2.1\,\frac{m}{s}[/tex], [tex]m_{t} = 0.3\,kg[/tex], [tex]m_{a} = 0.0225\,kg[/tex], [tex]v_{t,o} = 2.10\,\frac{m}{s}[/tex] and [tex]v_{t,f} = 0\,\frac{m}{s}[/tex], the speed of the arrow after passing through the target is:

[tex]v_{a,f} = 2.1\,\frac{m}{s} + \frac{0.3\,kg}{0.0225\,kg}\cdot (2.10\,\frac{m}{s} - 0\,\frac{m}{s} )[/tex]

[tex]v_{a,f} = 30.1\,\frac{m}{s}[/tex]

The speed of the arrow after passing through the target is 30.1 meters per second.

As an ice skater begins a spin, his angular speed is 3.14 rad/s. After pulling in his arms, his angular speed increases to 5.94 rad/s. Find the ratio of teh skater's final momentum of inertia to his initial momentum of inertia.

Answers

Answer:

I₂/I₁ = 0.53

Explanation:

During the motion the angular momentum of the skater remains conserved. Therefore:

Angular Momentum of Skater Before Pulling Arms = Angular Momentum of Skater After Pulling Arms

L₁ = L₂

but, the formula for angular momentum is:

L = Iω

Therefore,

I₁ω₁ = I₂ω₂

I₂/I₁ = ω₁/ω₂

where,

I₁ = Initial Moment of Inertia

I₂ = Final Moment of Inertia

ω₁ = Initial Angular Velocity = 3.14 rad/s

ω₂ = Final Angular velocity = 5.94 rad/s

Therefore,

I₂/I₁ = (3.14 rad/s)/(5.94 rad/s)

I₂/I₁ = 0.53

What must be the diameter of a cylindrical 120-m long metal wire if its resistance is to be ? The resistivity of this metal is 1.68 × 10-8 Ω • m.

Answers

Answer:

The  diameter is  [tex]d = 6.5 *10^{-4} \ m[/tex]

Explanation:

From the question we are told that

   The length of the cylinder is  [tex]l = 120 \ m[/tex]

     The resistance is  [tex]\ 6.0\ \Omega[/tex]

     The  resistivity of the metal is [tex]\rho = 1.68 *10^{-8} \ \Omega \cdot m[/tex]

Generally the resistance of the cylindrical wire is  mathematically represented as

         [tex]R = \rho \frac{l}{A }[/tex]

The cross-sectional area of the cylindrical wire is  

        [tex]A = \frac{\pi d^2}{4}[/tex]

Where  d is the diameter, so

         [tex]R = \rho \frac{l}{\frac{\pi d^2}{4 } }[/tex]

=>     [tex]d = \sqrt{ \rho* \frac{4 * l }{\pi * R } }[/tex]

       [tex]d = \sqrt{ 1.68 *10 ^{-8}* \frac{4 * 120 }{3.142 * 6 } }[/tex]

       [tex]d = 6.5 *10^{-4} \ m[/tex]

When a nucleus at rest spontaneously splits into fragments of mass m1 and m2, the ratio of the momentum of m1 to the momentum of m2 is

Answers

Answer:

  p₁ = - p₂

the moment value of the two particles is the same, but its direction is opposite

Explanation:

When a nucleus divides spontaneously, the moment of the nucleic must be conserved, for this we form a system formed by the initial nucleus and the two fragments of the fission, in this case the forces during the division are internal and the moment is conserved

initial instant. Before fission

               p₀ = 0

since they indicate that the nucleus is at rest

final moment. After fission

             [tex]p_{f}[/tex] = m₁ v₁ + m₂ v₂

             p₀ = p_{f}

             0 = m₁ v₁ + m₂v₂

             m₁ v₁ = -m₂ v₂

           

              p₁ = - p₂

this indicates that the moment value of the two particles is the same, but its direction is opposite

A small glass bead charged to 8.0 nC is in the plane that bisects a thin, uniformly charged, 10-cm long glass rod and is 4.0 cm from the rod's center. The bead is repelled from the rod with a force of 940 μN.

Required:
What is the total charge on the rod?

Answers

Answer:

71nC is the total charge of the rod

Explanation:

See attached file

The total charge on the rod is equal to 3.3 × 10⁻⁸ C.

What is the force on a charge in an electric field?

The force on the charge in a uniform electric field E is given by:

F = qE    where q is charge in coulombs

The electric field due to the charge associated with the rod is given by:

[tex]E =\frac{kQ}{r\sqrt{r+\frac{L^2}{4} } }[/tex]

Where r is the distance between the bead and the rod, L is the length of the glass rod and Q is the charge on the rod.

The force experienced by the bead charged is,

[tex]F =\frac{kqQ}{r\sqrt{r+\frac{L^2}{4} } }[/tex]

From the above equation, we can find the value of Q as:

[tex]Q =\frac{Fr\sqrt{r+\frac{L^2}{4} } }{kq}[/tex]

Given, the value of force, F = 940μN = 940 ×10⁻⁹ C

The length of glass rod, L = 10cm = 0.1 m and r = 4cm = 0.04 m

[tex]Q =\frac{(940\times 10^{-6}N)(0.04m)\sqrt{(0.04m)+\frac{(0.1m)^2}{4} } }{(8.99\times 10^9 N.m^2/C^2)(8\times 10^{-9}C)}[/tex]

[tex]Q= 0.5228\times 10^{-6}\times\sqrt{0.0041}[/tex]

[tex]Q = 3.3\times 10^{-8} C[/tex]

Therefore, the total charge on the rod is  3.3 × 10⁻⁸ C.

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Calculate the flow rate of blood (of density 0.846 g/cm3 ) in an aorta with a crosssectional area of 1.36 cm2 if the flow speed is 48.5 cm/s. Answer in units of g/s.

Answers

Answer:

55.80 g/s

Explanation:

From the question,

Flow rate = density×Area×velocity.

φ = ρ×A×V................... Equation 1

Where φ = flow rate of blood, ρ = density of blood, A = cross sectional area of blood, V = velocity of blood.

Given: ρ = 0.846 g/cm³, A = 1.36 cm², V = 48.5 cm/s.

Substitute these values into equation 1

φ = 0.846×1.36×48.5

φ = 55.80 g/s

Hence, the flow rate of  the blood = 55.80 g/s

You push very hard on a heavy desk, trying to move it. You do work on the desk: You push very hard on a heavy desk, trying to move it. You do work on the desk: whether or not it moves, as long as you are exerting a force. only if it starts moving. never-it does work on you. only if it doesn't move. None of the above.

Answers

Answer:

Only if it starts moving

Explanation:

Work done is defines as [tex]W=F.d=Fdcos\Theta[/tex]

In two case work done will be zero

First case is that when force and displacement are perpendicular to each other

What's more, other case is that when there is no displacement

So for work to be done there must have displacement,  in the event that there is no displacement then there is no work done

Find the length (in m) of an organ pipe closed at one end that produces a fundamental frequency of 175 Hz when air temperature is 18.0°C

Answers

Answer:

Length = 0.4882 m

Explanation:

given data

fundamental frequency = 175 Hz

air temperature = 18.0°C

solution

we will apply here fundamental frequency formula that is

F = [tex]\frac{v}{4L}[/tex]      ....................1

here v =   [tex]331 \sqrt{1+\frac{T}{273}}[/tex]  

here 331 m/s is speed of sound in air

so v =  [tex]331 \sqrt{1+\frac{18}{273}}[/tex]   = 341.74 m/s

now put value in equation 1 we get

F = [tex]\frac{v}{4L}[/tex]

[tex]175 = \frac{341.74}{4L}[/tex]  

Length = 0.4882 m

When we describe electric flux, we say that a surface is oriented in a certain direction with respect to an electric field. When we try to calculate how much electric field passes through the surface, we make use of the:_________.
1. Wedge Product
2. Dot Product
3. Cross Product

Answers

Answer:

2. Dot Product

Explanation:

The calculation of the electric flux gives an scalar result.

When we tray to calculate how much electric field passes trough a surface, we are calculating a scalar value. Furthermore, the concept of flux requires the calculation of a scalar value.

Also it is necessary to take into account that the magnitude of the flux trough a surface depends of the inclination of the surface respect to the direction of the electric field. This is taken into account sufficiently by a dot product.

Then, the answer is:

2. Dot Product

Two moons orbit a planet in nearly circular orbits. Moon A has orbital radius r, and moon B has orbital radius 16r. Moon A takes 10 days to complete one orbit. How long does it take moon B to complete an orbit

Answers

Answer:  

Kepler's Third Law:  The square of the period of any planet about the sun is proportional to cube of its mean distance from the sun.

Mathematically:  T^2 = K R^3

So  (TA / TB)^2 = (RA / RB)^3

TB^2 = TA^2 * (RB / RA)^3

TB^2 = 10^2 * 16^3

TB = (409600)^1/2 = 640 days

Now moving horizontally, the skier crosses a patch of soft snow, where the coefficient of friction is μk = 0.160. If the patch is of width 62.0 m and the average force of air resistance on the skier is 160 N , how fast is she going after crossing the patch?

Answers

Answer:

14.1 m/s

Explanation:

From the question,

μk = a/g...................... Equation 1

Where μk = coefficient of kinetic friction, a= acceleration of the skier, g = acceleration due to gravity.

make a the subject of the equation

a = μk(g).................. Equation 2

Given: μk = 0.160, g = 9.8 m/s²

Substitute into equation 2

a = 0.16(9.8)

a = 1.568 m/s²

Using,

F = ma

Where F = force, m = mass.

Make m the subject of the equation

m = F/a................... Equation 3

m = 160/1.568

m = 102.04 kg.

Note: The work done against air resistance by the skier+ work done against friction is equal to the kinetic energy after cross the patch.

Assuming the initial velocity of the skier to be zero

Fd+mgμ = 1/2mv²........................Equation 4

Where v = speed of the skier after crossing the patch, d = distance/width of the patch.

v = √2(Fd+mgμ)/m)................ Equation 5

Given: F = 160 N, m = 102.04 kg, d = 62 m, g = 9.8 m/s, μk = 0.16

Substitute these values into equation 5

v = √[2[(160×62)+(102.04×9.8×0.16)]/102.04]

v = √197.57

v = 14.1 m/s

v = 9.86 m/s

A satellite orbits the earth at a distance of 1.50 × 10^{7} m above the planetʹs surface and takes 8.65 hours for each revolution about the earth. The earthʹs radius is 6.38 × 10^{6} m. The acceleration of this satellite is closest to

Answers

Answer:

a = 0.43 m/s²

Explanation:

First, we need to find the velocity of the satellite:

Velocity = V = Distance Covered/Time Taken

here,

Distance = 1 revolution = 2π(1.5 x 10⁷ m) = 9.43 x 10⁷ m

Time = (8.65 hours)(3600 s/1 hour) = 31140 s

Therefore,

V = (9.43 x 10⁷ m)/(31140 s)

V = 3028.26 m/s

Now, the acceleration of the satellite will be equal to the centripetal acceleration, with the center of circular motion as the center of earth:

a = V²/R

where,

R = 1.5 x 10⁷ m + 0.638 x 10⁷ m

R = 2.138 x 10⁷ m

Therefore,

a = (3028.26 m/s)²/(2.138 x 10⁷ m)

a = 0.43 m/s²

A student is conducting an experiment that involves adding hydrochloric acid to various minerals to detect if they have carbonates in them. The student holds a mineral up and adds hydrochloric acid to it. The acid runs down the side and onto the student’s hand causing irritation and a minor burn. If they had done a risk assessment first, how would this situation be different? A. It would be the same, there is no way to predict the random chance of acid dripping off the mineral in a risk assessment. B. The student would have no injuries because he would know hydrochloric acid is dangerous and would be wearing gloves when using it. C. The student would be safer because he would have been wearing goggles, but his hand still would not have been protected. D. The student would not have picked up the mineral because he would know that some of the minerals have dangerous chemicals in them.

Answers

The answer would be D because it could have been prevented

By  the experiment "The student would have no injuries because he would know hydrochloric acid is dangerous and would be wearing gloves when using it. "

What is experiment ?

An experiment would be a technique used to confirm or deny a hypothesis, as well as assess the likelihood or effectiveness of something that has never been tried before.

What is hydrochloric acid?

Hydrochloric acid is a kind of compound in which hydrogen and chlorine element is present.

Maintain a safe distance between your hands and your body, mouth, eyes, as well as a face when utilizing lab supplies and chemicals.

By  the experiment "By  the experiment "The student would have no injuries because he would know hydrochloric acid is dangerous and would be wearing gloves when using it. "

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