Question 1

The net force acting on a 6.0-kg object is given by F_x = (12 - x) N, where F_x is in newtons and x is in meters. How much work is done on the object as it moves from x = 0 to x = 12 m?

Accepted Answer

B

Question 2

I use a rope 1.00-m-long to swing a 1.00-kg weight around my head. The tension in the rope is 20.0 N. In half a revolution how much work is done by the rope on the weight?

Accepted Answer

D

Question 3

In 1908 there was a huge explosion referred to as the Tunguska event which occurred in Siberia. Apparently this was caused by a very large meteorite, a small asteroid, or a comet colliding with the Earth. If the energy released, estimated at  J, were from the kinetic energy of the object, what would have been its approximate mass if its speed had been  m/s?

Accepted Answer

B

Question 4

The area under the force-displacement curve represents:

Accepted Answer

The area under the force-displacement curve represents the work done by the force over the displacement.

Question 5

A horizontal force of 200 N is applied to a 55-kg cart across a 10 m level surface. If the cart accelerates at 3.0 m/s², then what is the work done by the force of friction as it acts to retard the motion of the cart?

Accepted Answer

The answer of A horizontal force of 200 N is...

Question 6

A horizontal force of 100 N is applied to move a 45-kg cart across a 5.0-m level surface. What work is done by the 100-N force?

Accepted Answer

Work is defined as the product of force and distance, given by the formula W = Fd. In this case, the force is 100 N and the distance is 5.0 m. Therefore, W = (100 N)(5.0 m) = 500 J. Therefore, the correct answer is B.

Question 7

The net force acting on a 12.6-kg object is given by F_x = (8 - x) N, where F_x is in newtons and x is in meters. How much work is done on the object as it moves from x = 0 to x = 6 m?

Accepted Answer

The work done on the object as it moves from x = 0 to x = 6 m is equal to the area under the force versus displacement graph.

Using the given force equation, we can find the area:

W = ∫(8-x)dx from x=0 to x=6
W = [8x - (x^2)/2] from x=0 to x=6
W = (8*6 - (6^2)/2) - (8*0 - (0^2)/2)
W = 48 - 0
W = 48 J

Therefore, the correct answer is B) 30 J.

Question 8

A rock is thrown straight up with an initial velocity of 20.0 m/s. Ignore energy lost to air friction. How high will the rock rise?

Accepted Answer

Using the kinematic equation for height: 
h = v₀²/2g  
where 
h = maximum height 
v₀= initial velocity = 20.0 m/s 
g = acceleration due to gravity = 9.81 m/s² 
Plugging in the numbers: 
h = 20.0² / 2(9.81) = 20.4 m 
Therefore, the rock will rise up to a height of 20.4 meters. The correct answer is C).

Question 9

A 1200-kg automobile moving at 25 m/s has the brakes applied with a deceleration of 5.0 m/s². How far does the car travel before it stops?

Accepted Answer

The answer of A 1200-kg automobile moving at 25 m/s...

Question 10

The unit of work, joule, is dimensionally the same as:

Accepted Answer

Work is defined as the product of force and displacement, and the unit of force is newton and the unit of displacement is meter. Therefore, the unit of work is newton-meter, which is equivalent to joule.

Question 11

A very light cart holding a 300-N box is moved at constant velocity across a 15-m level surface. What is the total work done in the process?

Accepted Answer

When an object is moved at constant velocity, the net force acting on it is zero, which means the total work done is zero.

Question 12

A 5.00 kg ball falls from a 2.00 m-high shelf. Just before hitting the floor, what will be its kinetic energy? (g = 9.80 m/s² and assume air resistance is negligible)

Accepted Answer

When the ball falls from a height of 2.00 m, it gains potential energy due to gravity, which is given by:

Potential energy = mgh 
= 5.00 kg × 9.80 m/s2 × 2.00 m 
= 98.0 J

When the ball hits the ground, all of this potential energy is converted into kinetic energy. Therefore, its kinetic energy just before hitting the ground will also be 98.0 J.

Thus, the correct answer is choice A.

Question 13

Rupel pushes a box 4.00 m by applying a 25.0-N horizontal force. What work does she do?

Accepted Answer

Work = force x distance
Work = 25.0 N x 4.00 m
Work = 100 J

Question 14

A force of 200 N is applied to a 50-kg mass in the direction of motion for a distance of 6.0 m, and then the force is increased to 300 N for the next 5.0 m. For the 11 m of travel, how much work is done by the varying force?

Accepted Answer

The work done is calculated by summing the work done over each segment: W = F1 * d1 + F2 * d2 = 200 N * 6 m + 300 N * 5 m = 1200 J + 1500 J = 2700 J.

Question 15

A satellite is held in orbit by a 3000-N gravitational force. Each time the satellite completes an orbit of circumference 80,000 km, the work done on it by gravity is:

Accepted Answer

The work done by gravity on a satellite in a stable orbit is zero because the gravitational force is perpendicular to the direction of motion at every point in the orbit.

Question 16

What is the minimum amount of energy required for a 70.0-kg climber carrying a 20.0-kg pack to climb Mt. Everest, which is 8850 m high?

Accepted Answer

The answer of What is the minimum amount of energy...

Question 17

What is the kinetic energy of a 0.160-kg ball thrown at 40.0 m/s (90.0 mph)?

Accepted Answer

The answer of What is the kinetic energy of a...

Question 18

If during a given physical process the only force acting on an object is friction, which of the following must be assumed in regard to the object's kinetic energy?

Accepted Answer

The answer of If during a given physical process the...

Question 19

The work done by static friction can be:

Accepted Answer

Static friction does not do work because it acts on objects that are not moving relative to the surface they are on. However, theoretically, if it were to do work, it could be considered to have the potential to do positive, negative, or zero work depending on the scenario imagined, hence "Any of the above" is the most encompassing choice.

Question 20

A golf ball hits a wall and bounces back at 3/4 the original speed. What part of the original kinetic energy of the ball did it lose in the collision?

Accepted Answer

The answer of A golf ball hits a wall and...

Quiz 6: Work and Energy

The net force acting on a 6.0-kg object is given by F_x = (12 - x) N, where F_x is in newtons and x is in meters. How much work is done on the object as it moves from x = 0 to x = 12 m?

I use a rope 1.00-m-long to swing a 1.00-kg weight around my head. The tension in the rope is 20.0 N. In half a revolution how much work is done by the rope on the weight?

The area under the force-displacement curve represents:

A horizontal force of 200 N is applied to a 55-kg cart across a 10 m level surface. If the cart accelerates at 3.0 m/s², then what is the work done by the force of friction as it acts to retard the motion of the cart?

A horizontal force of 100 N is applied to move a 45-kg cart across a 5.0-m level surface. What work is done by the 100-N force?

The net force acting on a 12.6-kg object is given by F_x = (8 - x) N, where F_x is in newtons and x is in meters. How much work is done on the object as it moves from x = 0 to x = 6 m?

A rock is thrown straight up with an initial velocity of 20.0 m/s. Ignore energy lost to air friction. How high will the rock rise?

A 1200-kg automobile moving at 25 m/s has the brakes applied with a deceleration of 5.0 m/s². How far does the car travel before it stops?

The unit of work, joule, is dimensionally the same as:

A very light cart holding a 300-N box is moved at constant velocity across a 15-m level surface. What is the total work done in the process?

A 5.00 kg ball falls from a 2.00 m-high shelf. Just before hitting the floor, what will be its kinetic energy? (g = 9.80 m/s² and assume air resistance is negligible)

Rupel pushes a box 4.00 m by applying a 25.0-N horizontal force. What work does she do?

A force of 200 N is applied to a 50-kg mass in the direction of motion for a distance of 6.0 m, and then the force is increased to 300 N for the next 5.0 m. For the 11 m of travel, how much work is done by the varying force?

A satellite is held in orbit by a 3000-N gravitational force. Each time the satellite completes an orbit of circumference 80,000 km, the work done on it by gravity is:

What is the minimum amount of energy required for a 70.0-kg climber carrying a 20.0-kg pack to climb Mt. Everest, which is 8850 m high?

What is the kinetic energy of a 0.160-kg ball thrown at 40.0 m/s (90.0 mph) ?

If during a given physical process the only force acting on an object is friction, which of the following must be assumed in regard to the object's kinetic energy?

The work done by static friction can be:

A golf ball hits a wall and bounces back at 3/4 the original speed. What part of the original kinetic energy of the ball did it lose in the collision?

Quiz 6: Work and Energy

The net force acting on a 6.0-kg object is given by Fx = (12 - x) N, where Fx is in newtons and x is in meters. How much work is done on the object as it moves from x = 0 to x = 12 m?

I use a rope 1.00-m-long to swing a 1.00-kg weight around my head. The tension in the rope is 20.0 N. In half a revolution how much work is done by the rope on the weight?

The area under the force-displacement curve represents:

A horizontal force of 200 N is applied to a 55-kg cart across a 10 m level surface. If the cart accelerates at 3.0 m/s2, then what is the work done by the force of friction as it acts to retard the motion of the cart?

A horizontal force of 100 N is applied to move a 45-kg cart across a 5.0-m level surface. What work is done by the 100-N force?

The net force acting on a 12.6-kg object is given by Fx = (8 - x) N, where Fx is in newtons and x is in meters. How much work is done on the object as it moves from x = 0 to x = 6 m?

A rock is thrown straight up with an initial velocity of 20.0 m/s. Ignore energy lost to air friction. How high will the rock rise?

A 1200-kg automobile moving at 25 m/s has the brakes applied with a deceleration of 5.0 m/s2. How far does the car travel before it stops?

The unit of work, joule, is dimensionally the same as:

A very light cart holding a 300-N box is moved at constant velocity across a 15-m level surface. What is the total work done in the process?

A 5.00 kg ball falls from a 2.00 m-high shelf. Just before hitting the floor, what will be its kinetic energy? (g = 9.80 m/s2 and assume air resistance is negligible)

Rupel pushes a box 4.00 m by applying a 25.0-N horizontal force. What work does she do?

A force of 200 N is applied to a 50-kg mass in the direction of motion for a distance of 6.0 m, and then the force is increased to 300 N for the next 5.0 m. For the 11 m of travel, how much work is done by the varying force?

A satellite is held in orbit by a 3000-N gravitational force. Each time the satellite completes an orbit of circumference 80,000 km, the work done on it by gravity is:

What is the minimum amount of energy required for a 70.0-kg climber carrying a 20.0-kg pack to climb Mt. Everest, which is 8850 m high?

What is the kinetic energy of a 0.160-kg ball thrown at 40.0 m/s (90.0 mph) ?

If during a given physical process the only force acting on an object is friction, which of the following must be assumed in regard to the object's kinetic energy?

The work done by static friction can be:

A golf ball hits a wall and bounces back at 3/4 the original speed. What part of the original kinetic energy of the ball did it lose in the collision?

The net force acting on a 6.0-kg object is given by F_x = (12 - x) N, where F_x is in newtons and x is in meters. How much work is done on the object as it moves from x = 0 to x = 12 m?

A horizontal force of 200 N is applied to a 55-kg cart across a 10 m level surface. If the cart accelerates at 3.0 m/s², then what is the work done by the force of friction as it acts to retard the motion of the cart?

The net force acting on a 12.6-kg object is given by F_x = (8 - x) N, where F_x is in newtons and x is in meters. How much work is done on the object as it moves from x = 0 to x = 6 m?

A 1200-kg automobile moving at 25 m/s has the brakes applied with a deceleration of 5.0 m/s². How far does the car travel before it stops?

A 5.00 kg ball falls from a 2.00 m-high shelf. Just before hitting the floor, what will be its kinetic energy? (g = 9.80 m/s² and assume air resistance is negligible)