Question 1

Two cars collide,lock bumpers,and eventually slide to a stop due to friction with the roadway.During this entire process,mechanical energy and momentum are both conserved.

Accepted Answer

A) True 
 B)False

Question 2

A 3.5 kg mass is pressed against a spring of spring constant 90.0 N/m,compressing it 25.0 cm.The greatest amount of kinetic energy this mass could gain after it is released is 2.81 J.

Accepted Answer

A) True 
 B)False

Question 3

Calculate the average power output necessary for a 55.8 kg person to run up a 12.0 m long hillside,which is inclined at 25.0° above the horizontal,in 3.00 s.Express your answer in horsepower.

Accepted Answer

A) 1.24 hp 
B) 2.93 hp 
C) 1.86 hp 
D) 0.74 hp 
A) 1.24 hp 
B) 2.93 hp 
C) 1.86 hp 
D) 0.74 hp

Question 4

If a force acts perpendicular to an object's direction of motion,that force cannot change the object's kinetic energy or momentum.

Accepted Answer

A) True 
 B)False

Question 5

The frame of a cart has a mass of 45 kg,and the cart rolls on four railroad car wheels,each with a mass of 22 kg.The cart is being ridden at a speed of 5.0 m/s by a 75 kg man.What is the total kinetic energy? (Model the railroad car wheels as solid uniform disks of radius 20 cm. )

Accepted Answer

A) 3200 J 
B) 1900 J 
C) 2100 J 
D) 2200 J 
A) 3200 J 
B) 1900 J 
C) 2100 J 
D) 2200 J

Question 6

Two lumps of clay are thrown at each other such that they come completely to rest after the collision.Obviously,kinetic energy is not conserved.Where did the energy go?

Accepted Answer

The kinetic energy of the two

Question 7

A cannon recoils after it fires a shell.If you measure the range of the shell,can you find the energy released by the gunpowder?

Accepted Answer

No.During the same time it tak

Question 8

A crane lifts a 425 kg steel beam vertically upward a distance of 117 m.How much work does the crane do on the beam if the beam accelerates upward at 1.8 m/s2? Neglect frictional forces.

Accepted Answer

A) 5.8 × 105 J 
B) 3.4 × 105J 
C) 4.0 × 105 J 
D) 4.9 × 105 J 
A) 5.8 × 105 J 
B) 3.4 × 105J 
C) 4.0 × 105 J 
D) 4.9 × 105 J

Question 9

A 2.0 kg stone slides from rest down a hill 5.0 m high and is observed to be moving at 6.0 m/s at the bottom.During this process,62 J of thermal energy have been produced.

Accepted Answer

A) True 
 B)False

Question 10

Three cars (car F,car G,and car H)are moving with the same velocity,and slam on the brakes.The most massive car is car F,and the least massive is car H.Assuming all three cars have identical tires,which car travels the longest distance to skid to a stop?

Accepted Answer

A) They all travel the same distance in stopping. 
B) Car F. 
C) Car G. 
D) Car H. 
A) They all travel the same distance in stopping. 
B) Car F. 
C) Car G. 
D) Car H.

Question 11

Viscous friction allows oil to reduce the heating and wear of moving machine parts.But viscous friction depends on velocity.Is that a nonconservative force?

Accepted Answer

Yes,whatever the functional de

Question 12

A rubber ball is dropped from a height h above the ground.Describe the motion of the ball for many bounces if the collision is completely elastic.

Accepted Answer

If the collision is completely elastic,t

Question 13

You carry a 7.0 kg bag of groceries 1.2 m above the ground at constant velocity across a 2.3 m room.How much work do you do on the bag in the process?

Accepted Answer

A) 0.0 J 
B) 82 J 
C) 158 J 
D) 134 J 
A) 0.0 J 
B) 82 J 
C) 158 J 
D) 134 J

Question 14

Two pendulums of equal length l = 0.45 m are suspended from the same point.The pendulum bobs are steel spheres.The first bob is drawn back to make a 35° angle with the vertical.If the first bob has mass 0.25 kg and the second has mass 0.85 kg,how high will the second bob rise above its initial position when struck elastically by the first bob after it is released?

Accepted Answer

A) 1.7 cm 
B) 1.4 cm 
C) 2.0 cm 
D) 2.3 cm 
A) 1.7 cm 
B) 1.4 cm 
C) 2.0 cm 
D) 2.3 cm

Question 15

A child does 350 J of work while pulling a box from the ground up to his tree house with a rope.The tree house is 8.4 m above the ground.What is the mass of the box?

Accepted Answer

A) 4.3 kg 
B) 2.6 kg 
C) 3.2 kg 
D) 3.9 kg 
A) 4.3 kg 
B) 2.6 kg 
C) 3.2 kg 
D) 3.9 kg

Question 16

A car needs to generate 75.0 hp in order to maintain a constant velocity of 27.3 m/s on a flat road.What is the magnitude of the total resistive force acting on the car (due to friction,air resistance,etc. )?

Accepted Answer

A) 2.05 × 103 N 
B) 2.75 N 
C) 1.03 × 103 N 
D) 2.87 × 103 N 
A) 2.05 × 103 N 
B) 2.75 N 
C) 1.03 × 103 N 
D) 2.87 × 103 N

Question 17

A traveler pulls on a suitcase strap at an angle 36° above the horizontal.If 908 J of work are done by the strap while moving the suitcase a horizontal distance of 15 m,what is the tension in the strap?

Accepted Answer

A) 75 N 
B) 61 N 
C) 85 N 
D) 92 N 
A) 75 N 
B) 61 N 
C) 85 N 
D) 92 N

Question 18

Kinetic energy is conserved only in perfectly elastic collisions,but momentum is conserved in all collisions.

Accepted Answer

A) True 
 B)False

Question 19

A pendulum in a grandfather clock swings back and forth.Does the force of gravity do positive work on the pendulum at any point in its trajectory? If so,where?

Accepted Answer

The force of gravity does positive work

Question 20

A 1000.0 kg car experiences a net force of 9500 N while decelerating from 30.0 m/s to 23.4 m/s.How far does it travel while slowing down?

Accepted Answer

A) 19 m 
B) 17 m 
C) 20 m 
D) 22 m 
A) 19 m 
B) 17 m 
C) 20 m 
D) 22 m

Exam 10: Energy and Work

Two cars collide,lock bumpers,and eventually slide to a stop due to friction with the roadway.During this entire process,mechanical energy and momentum are both conserved.

A 3.5 kg mass is pressed against a spring of spring constant 90.0 N/m,compressing it 25.0 cm.The greatest amount of kinetic energy this mass could gain after it is released is 2.81 J.

Calculate the average power output necessary for a 55.8 kg person to run up a 12.0 m long hillside,which is inclined at 25.0° above the horizontal,in 3.00 s.Express your answer in horsepower.

If a force acts perpendicular to an object's direction of motion,that force cannot change the object's kinetic energy or momentum.

The frame of a cart has a mass of 45 kg,and the cart rolls on four railroad car wheels,each with a mass of 22 kg.The cart is being ridden at a speed of 5.0 m/s by a 75 kg man.What is the total kinetic energy? (Model the railroad car wheels as solid uniform disks of radius 20 cm. )

Two lumps of clay are thrown at each other such that they come completely to rest after the collision.Obviously,kinetic energy is not conserved.Where did the energy go?

A cannon recoils after it fires a shell.If you measure the range of the shell,can you find the energy released by the gunpowder?

A crane lifts a 425 kg steel beam vertically upward a distance of 117 m.How much work does the crane do on the beam if the beam accelerates upward at 1.8 m/s2? Neglect frictional forces.

A 2.0 kg stone slides from rest down a hill 5.0 m high and is observed to be moving at 6.0 m/s at the bottom.During this process,62 J of thermal energy have been produced.

Three cars (car F,car G,and car H)are moving with the same velocity,and slam on the brakes.The most massive car is car F,and the least massive is car H.Assuming all three cars have identical tires,which car travels the longest distance to skid to a stop?

Viscous friction allows oil to reduce the heating and wear of moving machine parts.But viscous friction depends on velocity.Is that a nonconservative force?

A rubber ball is dropped from a height h above the ground.Describe the motion of the ball for many bounces if the collision is completely elastic.

You carry a 7.0 kg bag of groceries 1.2 m above the ground at constant velocity across a 2.3 m room.How much work do you do on the bag in the process?

A child does 350 J of work while pulling a box from the ground up to his tree house with a rope.The tree house is 8.4 m above the ground.What is the mass of the box?

A car needs to generate 75.0 hp in order to maintain a constant velocity of 27.3 m/s on a flat road.What is the magnitude of the total resistive force acting on the car (due to friction,air resistance,etc. )?

A traveler pulls on a suitcase strap at an angle 36° above the horizontal.If 908 J of work are done by the strap while moving the suitcase a horizontal distance of 15 m,what is the tension in the strap?

Kinetic energy is conserved only in perfectly elastic collisions,but momentum is conserved in all collisions.

A pendulum in a grandfather clock swings back and forth.Does the force of gravity do positive work on the pendulum at any point in its trajectory? If so,where?

A 1000.0 kg car experiences a net force of 9500 N while decelerating from 30.0 m/s to 23.4 m/s.How far does it travel while slowing down?

Representing Motion

Motion in One Dimension

Vectors and Motion in Two Dimensions

Forces and Newtons Laws of Motion

Applying Newtons Laws

Circular Motion,orbits,and Gravity

Rotational Motion

Equilibrium and Elasticity

Momentum

Using Energy

Thermal Properties of Matter

Fluids

Oscillations

Traveling Waves and Sound

Superposition and Standing Waves

Wave Optics

Ray Optics

Optical Instruments

Electric Fields and Forces

Electric Potential

Current and Resistance

Circuits

Magnetic Fields and Forces

Electromagnetic Induction and Electromagnetic Waves

Ac Electricity

Relativity

Quantum Physics

Atoms and Molecules

Nuclear Physics

Filters

A crane lifts a 425 kg steel beam vertically upward a distance of 117 m.How much work does the crane do on the beam if the beam accelerates upward at 1.8 m/s²? Neglect frictional forces.