Question 1

If both mass and velocity of a ball are tripled,the kinetic energy is increased by a factor of:

Accepted Answer

A) 3. 
B) 6. 
C) 9. 
D) 27. 
A) 3. 
B) 6. 
C) 9. 
D) 27.

Question 2

A boat with mass 950 kg is heading into the harbor at a speed of 10.0 m/s.How much work is required to slow the boat to 1.0 m/s?

Accepted Answer

A) 4.8E+4 J 
B) 9.4E+4 J 
C) 4.7E+4 J 
D) 2.3E+4 J 
A) 4.8E+4 J 
B) 9.4E+4 J 
C) 4.7E+4 J 
D) 2.3E+4 J

Question 3

A 6.1-g bullet has a velocity of 475 m/s when it penetrates a wooden door to a depth of 3.5 cm.Assuming the frictional force that stops the bullet is constant,how long does it take from the time the bullet hits the door till it comes to a stop?

Accepted Answer

A) 1.5E-4 s 
B) 7.4E-5 s 
C) 4.5E-2 s 
D) 3.7E-3 s 
A) 1.5E-4 s 
B) 7.4E-5 s 
C) 4.5E-2 s 
D) 3.7E-3 s

Question 4

A 100-W light bulb is left on for 8.0 hours.Over this period of time,how much energy was used by the bulb?

Accepted Answer

A) 8.0E+2 J 
B) 2.9E+5 J 
C) 2.9E+6 J 
D) 1.34 hp 
E) 2.9E+4 J 
A) 8.0E+2 J 
B) 2.9E+5 J 
C) 2.9E+6 J 
D) 1.34 hp 
E) 2.9E+4 J

Question 5

When an object is dropped from a tower,what is the effect of the air resistance as it falls?

Accepted Answer

A) does positive work 
B) increases the object's kinetic energy 
C) increases the object's potential energy 
D) None of the above choices are valid. 
A) does positive work 
B) increases the object's kinetic energy 
C) increases the object's potential energy 
D) None of the above choices are valid.

Question 6

A Hooke's law spring is compressed a distance d and is used to launch a mass m vertically to a height h above its starting position.Under double the compression,the spring is now used to launch the mass.How high does the mass now rise above its starting position?

Accepted Answer

A) 2h 
B)    h 
C) 3h 
D) 4h 
A) 2h 
B)    h 
C) 3h 
D) 4h

Question 7

An Olympic skier moving at 19.5 m/s down a 17.0° slope encounters a region of wet snow,of coefficient of friction μk = 0.740.How far down the slope does she go before stopping?

Accepted Answer

A) 56.7 m 
B) 46.7 m 
C) 56.1 m 
D) 36.7 m 
E) 37.4 m 
A) 56.7 m 
B) 46.7 m 
C) 56.1 m 
D) 36.7 m 
E) 37.4 m

Question 8

A simple pendulum,1.00 m in length,is released from rest when the support string is at an angle of 48.0° from the vertical.What is the speed of the suspended mass at the bottom of the swing? (g = 9.80 m/s2 and ignore air resistance)

Accepted Answer

A) 4.43 m/s 
B) 3.82 m/s 
C) 6.49 m/s 
D) 2.55 m/s 
E) 1.62 m/s 
A) 4.43 m/s 
B) 3.82 m/s 
C) 6.49 m/s 
D) 2.55 m/s 
E) 1.62 m/s

Question 9

Preston pushes a wheelbarrow weighing 480 N to the top of a 45.0-m ramp,inclined at 22.0° with the horizontal,and leaves it.Tamara accidentally bumps the wheelbarrow.It slides back down the ramp,during which an 85.0-N frictional force acts on it over the 45.0 m.What is the wheelbarrow's kinetic energy at the bottom at of the ramp? (g = 9.8 m/s2)

Accepted Answer

A) 1.4E+3 J 
B) 1.6E+4 J 
C) 1.2E+4 J 
D) 8.1E+3 J 
E) 4.3E+3 J 
A) 1.4E+3 J 
B) 1.6E+4 J 
C) 1.2E+4 J 
D) 8.1E+3 J 
E) 4.3E+3 J

Question 10

A boat with mass of 1 200 kg is traveling at 12 m/s.What is the magnitude of the force required to stop the boat if it undergoes a displacement of 85 m?

Accepted Answer

A) 2 000 N 
B) 170 N 
C) 8 500 N 
D) 1 000 N 
A) 2 000 N 
B) 170 N 
C) 8 500 N 
D) 1 000 N

Question 11

The net force acting on a 4.92-kg object is given by Fx = (10 − 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 = 12.4 m?

Accepted Answer

A) 61.0 J 
B) 12.4 J 
C) 47.1 J 
D) 23.6 J 
E) 35.3 J 
A) 61.0 J 
B) 12.4 J 
C) 47.1 J 
D) 23.6 J 
E) 35.3 J

Question 12

An airliner with mass 90 000 kg is flying at 900 km/h at a height of 15.0 km.What is its total energy (kinetic + potential)if the total was 0 when the airliner was at rest on the ground?

Accepted Answer

A) 5.0E+10 J 
B) 3.6E+10 J 
C) 1.3E+10 J 
D) zero 
E) 1.6E+10 J 
A) 5.0E+10 J 
B) 3.6E+10 J 
C) 1.3E+10 J 
D) zero 
E) 1.6E+10 J

Question 13

A 2 500-kg car is moving at 2.30 m/s.How fast must a 1.5-kg toy car be moving so that the two have the same kinetic energy?

Accepted Answer

A) 61.9 m/s 
B) 3.97 m/s 
C) 93.9 m/s 
D) 6 610 m/s 
A) 61.9 m/s 
B) 3.97 m/s 
C) 93.9 m/s 
D) 6 610 m/s

Question 14

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

A) 1/4 
B) 3/8 
C) 7/16 
D) 9/16 
E) ​3/4 
A) 1/4 
B) 3/8 
C) 7/16 
D) 9/16 
E) ​3/4

Question 15

A very light cart holding a 100-N box is moved at constant velocity across a 10-m level surface.What is the net work done in the process?

Accepted Answer

A) zero 
B) 1/10 J 
C) 10 J 
D) 100 J 
E) ​1 000 J 
A) zero 
B) 1/10 J 
C) 10 J 
D) 100 J 
E) ​1 000 J

Question 16

The force acting on an object is given by Fx = (5x - 10)N,where x is in meters.What is the net work done by the force as the object moves from x = 0 to x = 4.50?

Accepted Answer

A) 5.6 J 
B) 15.6 J 
C) 12.5 J 
D) 11.3 J 
A) 5.6 J 
B) 15.6 J 
C) 12.5 J 
D) 11.3 J

Question 17

The work done by static friction can be:

Accepted Answer

A) positive. 
B) negative. 
C) zero. 
D) Any of the above. 
A) positive. 
B) negative. 
C) zero. 
D) Any of the above.

Question 18

A horizontal force of 85.0 N is applied to move a 46.0-kg cart across a 4.0-m level surface.What work is done by the 85.0-N force?

Accepted Answer

A) 7.4E+0 J 
B) 1.6E+4 J 
C) 3.4E+2 J 
D) 9.8E+2 J 
E) 4.6E-1 J 
A) 7.4E+0 J 
B) 1.6E+4 J 
C) 3.4E+2 J 
D) 9.8E+2 J 
E) 4.6E-1 J

Question 19

A 60-kg (including the passenger)sled is subject to a net force of 20 N pushing in the direction of the sled's motion as it is moving over a horizontal surface for a distance of 11 m after having started from rest.At this point the sled is released as it starts down a 10.0° incline.However,the snow is not very deep,and the sled stops after having moved an additional 35 m.What is the work done by friction while the sled is on the incline?

Accepted Answer

A) -3.6E+3 J 
B) -3.8E+3 J 
C) -3.4E+3 J 
D) -2.0E+4 J 
A) -3.6E+3 J 
B) -3.8E+3 J 
C) -3.4E+3 J 
D) -2.0E+4 J

Question 20

A satellite is held in orbit by a 1 000-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

A) 1.0×108 J. 
B) 8.0×108 J. 
C) 1.0×1011 J. 
D) 0. 
E) ​8.0×1011 J. 
A) 1.0×108 J. 
B) 8.0×108 J. 
C) 1.0×1011 J. 
D) 0. 
E) ​8.0×1011 J.

Exam 5: Energy

If both mass and velocity of a ball are tripled,the kinetic energy is increased by a factor of:

A boat with mass 950 kg is heading into the harbor at a speed of 10.0 m/s.How much work is required to slow the boat to 1.0 m/s?

A 6.1-g bullet has a velocity of 475 m/s when it penetrates a wooden door to a depth of 3.5 cm.Assuming the frictional force that stops the bullet is constant,how long does it take from the time the bullet hits the door till it comes to a stop?

A 100-W light bulb is left on for 8.0 hours.Over this period of time,how much energy was used by the bulb?

When an object is dropped from a tower,what is the effect of the air resistance as it falls?

A Hooke's law spring is compressed a distance d and is used to launch a mass m vertically to a height h above its starting position.Under double the compression,the spring is now used to launch the mass.How high does the mass now rise above its starting position?

An Olympic skier moving at 19.5 m/s down a 17.0° slope encounters a region of wet snow,of coefficient of friction μk = 0.740.How far down the slope does she go before stopping?

A simple pendulum,1.00 m in length,is released from rest when the support string is at an angle of 48.0° from the vertical.What is the speed of the suspended mass at the bottom of the swing? (g = 9.80 m/s2 and ignore air resistance)

A boat with mass of 1 200 kg is traveling at 12 m/s.What is the magnitude of the force required to stop the boat if it undergoes a displacement of 85 m?

The net force acting on a 4.92-kg object is given by Fx = (10 − 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 = 12.4 m?

An airliner with mass 90 000 kg is flying at 900 km/h at a height of 15.0 km.What is its total energy (kinetic + potential)if the total was 0 when the airliner was at rest on the ground?

A 2 500-kg car is moving at 2.30 m/s.How fast must a 1.5-kg toy car be moving so that the two have the same kinetic energy?

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?

A very light cart holding a 100-N box is moved at constant velocity across a 10-m level surface.What is the net work done in the process?

The force acting on an object is given by Fx = (5x - 10)N,where x is in meters.What is the net work done by the force as the object moves from x = 0 to x = 4.50?

The work done by static friction can be:

A horizontal force of 85.0 N is applied to move a 46.0-kg cart across a 4.0-m level surface.What work is done by the 85.0-N force?

A satellite is held in orbit by a 1 000-N gravitational force.Each time the satellite completes an orbit of circumference 80 000 km,the work done on it by gravity is:

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An Olympic skier moving at 19.5 m/s down a 17.0° slope encounters a region of wet snow,of coefficient of friction μ_k = 0.740.How far down the slope does she go before stopping?

A simple pendulum,1.00 m in length,is released from rest when the support string is at an angle of 48.0° from the vertical.What is the speed of the suspended mass at the bottom of the swing? (g = 9.80 m/s² and ignore air resistance)

The net force acting on a 4.92-kg object is given by F_x = (10 − 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 = 12.4 m?

The force acting on an object is given by F_x = (5x - 10)N,where x is in meters.What is the net work done by the force as the object moves from x = 0 to x = 4.50?