Question 1

A stalled car is being pushed up a hill by three people,and it is moving at a constant speed.The net force on the car is

Accepted Answer

A) zero. 
B) in the same direction of the car's motion. 
C) in the opposite direction of the car's motion. 
D) None of the above 
A) zero. 
B) in the same direction of the car's motion. 
C) in the opposite direction of the car's motion. 
D) None of the above

Question 2

The figure shows an acceleration-versus-force graph for a 125 g object.What should be the value of the first tick-mark on the vertical scale?

Accepted Answer

A) 4 
B) 8 
C) 0.00400 
D) 0.00800 
A) 4 
B) 8 
C) 0.00400 
D) 0.00800

Question 3

You are making a circular turn in your car when you hit a big patch of ice,causing the force of friction between the tires and the road to become zero.While the car is on the ice,it

Accepted Answer

A) moves along a straight-line path. 
B) continues to follow a circular path,but with a radius larger than the original radius. 
C) moves along a path that is neither straight nor circular. 
D) continues to follow the same circular path as initially. 
A) moves along a straight-line path. 
B) continues to follow a circular path,but with a radius larger than the original radius. 
C) moves along a path that is neither straight nor circular. 
D) continues to follow the same circular path as initially.

Question 4

A ball is thrown vertically upward,reaches a highest point,and comes back down.At the top of its path,what forces,if any,act on the ball? Explain your answer.

Accepted Answer

A) no forces 
B) only a downward force 
C) only an upward force 
D) an upward and a downward force,opposing and equal 
A) no forces 
B) only a downward force 
C) only an upward force 
D) an upward and a downward force,opposing and equal

Question 5

If a 5.0 kg box is pulled simultaneously by a 10.0 N force and a 5.0 N force,then its acceleration must be 3.0 m/s2.

Accepted Answer

A) True 
 B)False

Question 6

A bucket is being lowered by a rope with a constant downward acceleration.The tension in the rope must be equal to the weight of the bucket.

Accepted Answer

A) True 
 B)False

Question 7

An object is moving to the right,and experiencing a net force that is directed to the right.The magnitude of the force is decreasing with time.The speed of the object is

Accepted Answer

A) increasing. 
B) decreasing. 
C) constant in time. 
A) increasing. 
B) decreasing. 
C) constant in time.

Question 8

A satellite is in orbit around the earth.The satellite pulls just as hard on the earth as the earth pulls on the satellite.

Accepted Answer

A) True 
 B)False

Question 9

It takes 4500 N to accelerate a car at a rate of 3.42 m/s2.What is the mass of the car?

Accepted Answer

A) 1310 kg 
B) 1700 kg 
C) 1510 kg 
D) 1040 kg 
A) 1310 kg 
B) 1700 kg 
C) 1510 kg 
D) 1040 kg

Question 10

Two forces act on a 55 kg object.One force has magnitude 65 N directed 59° clockwise from the positive x-axis,and the other has a magnitude 35 N at 32° clockwise from the positive y-axis.What is the magnitude of this object's acceleration?

Accepted Answer

A) 1.1 m/s2 
B) 1.3 m/s2 
C) 1.5 m/s2 
D) 1.7 m/s2 
A) 1.1 m/s2 
B) 1.3 m/s2 
C) 1.5 m/s2 
D) 1.7 m/s2

Question 11

A child on a sled starts from rest at the top of a 15.0° slope.If the trip to the bottom takes 15.2 s,how long is the slope? Assume that frictional forces may be neglected.

Accepted Answer

A) 293 m 
B) 586 m 
C) 1130 m 
D) 147 m 
A) 293 m 
B) 586 m 
C) 1130 m 
D) 147 m

Question 12

If you jumped out of a plane,you would begin speeding up as you fall downward.Eventually,due to wind resistance,your velocity would become constant with time.After this occurs,the magnitude of the force of wind resistance is

Accepted Answer

A) equal to the force of gravity acting on you. 
B) is much smaller than the force of gravity acting on you. 
C) is slightly smaller than the force of gravity acting on you. 
D) is greater than the force of gravity acting on you. 
A) equal to the force of gravity acting on you. 
B) is much smaller than the force of gravity acting on you. 
C) is slightly smaller than the force of gravity acting on you. 
D) is greater than the force of gravity acting on you.

Question 13

The figure shows two forces acting on an object.They have magnitudes F1 = 6.3 N and F2 = 2.1 N.What third force will cause the object to be in equilibrium?

Accepted Answer

A) 6.6 N at 162° counterclockwise from   
B) 6.6 N at 108° counterclockwise from   
C) 4.2 N at 162° counterclockwise from   
D) 4.2 N at 108° counterclockwise from   
A) 6.6 N at 162° counterclockwise from   
B) 6.6 N at 108° counterclockwise from   
C) 4.2 N at 162° counterclockwise from   
D) 4.2 N at 108° counterclockwise from

Question 14

The figure shows two forces acting on an object,with magnitudes F1 = 78 N and F2 = 26 N.What third force will cause the object to be in equilibrium?

Accepted Answer

A) 52 N pointing down 
B) 52 N pointing up 
C) 82 N pointing down 
D) 82 N pointing up 
A) 52 N pointing down 
B) 52 N pointing up 
C) 82 N pointing down 
D) 82 N pointing up

Question 15

Suppose the force of wind resistance is proportional to the speed of the object and in the direction opposite the object's velocity.If you throw an object upward,when is the magnitude of the acceleration the highest?

Accepted Answer

A) It is highest right after the object is released. 
B) It is highest at the top of its trajectory. 
C) The acceleration of the object is the same throughout the entire trajectory. 
A) It is highest right after the object is released. 
B) It is highest at the top of its trajectory. 
C) The acceleration of the object is the same throughout the entire trajectory.

Question 16

Under the action of a constant force an object accelerates at 7.8 m/s2.What will the acceleration be if (a)The force is halved? (b)The object's mass is halved? (c)The force and the object's mass are both halved? (d)The force is halved and the object's mass is doubled?

Accepted Answer

A) (a)3.9 m/s2, (b)16 m/s2, (c)7.8 m/s2, (d)2.0 m/s2 
B) (a)16 m/s2, (b)3.9 m/s2, (c)2.0 m/s2, (d)7.8 m/s2 
C) (a)3.9 m/s2, (b)16 m/s2, (c)2.0 m/s2, (d)7.8 m/s2 
D) (a)3.9 m/s2, (b)16 m/s2, (c)7.8 m/s2, (d)7.8 m/s2 
A) (a)3.9 m/s2, (b)16 m/s2, (c)7.8 m/s2, (d)2.0 m/s2 
B) (a)16 m/s2, (b)3.9 m/s2, (c)2.0 m/s2, (d)7.8 m/s2 
C) (a)3.9 m/s2, (b)16 m/s2, (c)2.0 m/s2, (d)7.8 m/s2 
D) (a)3.9 m/s2, (b)16 m/s2, (c)7.8 m/s2, (d)7.8 m/s2

Question 17

Joe and Bill are playing tug-of-war.Joe is pulling with a force of 200 N.Bill is simply hanging on to the rope.Neither person is moving.What is the tension of the rope?

Accepted Answer

A) 200 N 
B) 400 N 
C) 0 N 
D) 300 N 
A) 200 N 
B) 400 N 
C) 0 N 
D) 300 N

Question 18

A person gives a shopping cart an initial push along a horizontal floor to get it moving,and then lets go.The cart travels forward along the floor,gradually slowing as it moves.Consider the horizontal force(s)on the cart while it is moving forward and slowing.Which of the following statements is correct?

Accepted Answer

A) Both a forward and a backward force are acting on the cart,but the forward force is larger. 
B) Both a forward and a backward force are acting on the cart,but the backward force is larger. 
C) Only a forward force is acting,which diminishes with time. 
D) Only a backward force is acting,no forward force. 
A) Both a forward and a backward force are acting on the cart,but the forward force is larger. 
B) Both a forward and a backward force are acting on the cart,but the backward force is larger. 
C) Only a forward force is acting,which diminishes with time. 
D) Only a backward force is acting,no forward force.

Question 19

An object accelerates at 4.1 m/s2 under the action of two rubber bands.What will be the object's acceleration if it is pulled by four rubber bands?

Accepted Answer

A) 8.2 m/s2 
B) 16 m/s2 
C) 4.1 m/s2 
D) 2.1 m/s2 
A) 8.2 m/s2 
B) 16 m/s2 
C) 4.1 m/s2 
D) 2.1 m/s2

Question 20

In outer space,an astronaut is working with two pieces of equipment that are outwardly identical.However,one of the objects has a slightly larger mass than the other.Since objects are weightless in space,how can the astronaut distinguish between the two objects?

Accepted Answer

The objects are weightless in

Exam 4: Forces and Newtons Laws of Motion

A stalled car is being pushed up a hill by three people,and it is moving at a constant speed.The net force on the car is

The figure shows an acceleration-versus-force graph for a 125 g object.What should be the value of the first tick-mark on the vertical scale?

You are making a circular turn in your car when you hit a big patch of ice,causing the force of friction between the tires and the road to become zero.While the car is on the ice,it

A ball is thrown vertically upward,reaches a highest point,and comes back down.At the top of its path,what forces,if any,act on the ball? Explain your answer.

If a 5.0 kg box is pulled simultaneously by a 10.0 N force and a 5.0 N force,then its acceleration must be 3.0 m/s2.

A bucket is being lowered by a rope with a constant downward acceleration.The tension in the rope must be equal to the weight of the bucket.

An object is moving to the right,and experiencing a net force that is directed to the right.The magnitude of the force is decreasing with time.The speed of the object is

A satellite is in orbit around the earth.The satellite pulls just as hard on the earth as the earth pulls on the satellite.

It takes 4500 N to accelerate a car at a rate of 3.42 m/s2.What is the mass of the car?

Two forces act on a 55 kg object.One force has magnitude 65 N directed 59° clockwise from the positive x-axis,and the other has a magnitude 35 N at 32° clockwise from the positive y-axis.What is the magnitude of this object's acceleration?

A child on a sled starts from rest at the top of a 15.0° slope.If the trip to the bottom takes 15.2 s,how long is the slope? Assume that frictional forces may be neglected.

If you jumped out of a plane,you would begin speeding up as you fall downward.Eventually,due to wind resistance,your velocity would become constant with time.After this occurs,the magnitude of the force of wind resistance is

The figure shows two forces acting on an object.They have magnitudes F1 = 6.3 N and F2 = 2.1 N.What third force will cause the object to be in equilibrium?

The figure shows two forces acting on an object,with magnitudes F1 = 78 N and F2 = 26 N.What third force will cause the object to be in equilibrium?

Suppose the force of wind resistance is proportional to the speed of the object and in the direction opposite the object's velocity.If you throw an object upward,when is the magnitude of the acceleration the highest?

Under the action of a constant force an object accelerates at 7.8 m/s2.What will the acceleration be if (a)The force is halved? (b)The object's mass is halved? (c)The force and the object's mass are both halved? (d)The force is halved and the object's mass is doubled?

Joe and Bill are playing tug-of-war.Joe is pulling with a force of 200 N.Bill is simply hanging on to the rope.Neither person is moving.What is the tension of the rope?

An object accelerates at 4.1 m/s2 under the action of two rubber bands.What will be the object's acceleration if it is pulled by four rubber bands?

In outer space,an astronaut is working with two pieces of equipment that are outwardly identical.However,one of the objects has a slightly larger mass than the other.Since objects are weightless in space,how can the astronaut distinguish between the two objects?

Representing Motion

Motion in One Dimension

Vectors and Motion in Two Dimensions

Applying Newtons Laws

Circular Motion,orbits,and Gravity

Rotational Motion

Equilibrium and Elasticity

Momentum

Energy and Work

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

If a 5.0 kg box is pulled simultaneously by a 10.0 N force and a 5.0 N force,then its acceleration must be 3.0 m/s².

It takes 4500 N to accelerate a car at a rate of 3.42 m/s².What is the mass of the car?

The figure shows two forces acting on an object.They have magnitudes F₁ = 6.3 N and F₂ = 2.1 N.What third force will cause the object to be in equilibrium?

The figure shows two forces acting on an object,with magnitudes F₁ = 78 N and F₂ = 26 N.What third force will cause the object to be in equilibrium?

Under the action of a constant force an object accelerates at 7.8 m/s².What will the acceleration be if (a)The force is halved? (b)The object's mass is halved? (c)The force and the object's mass are both halved? (d)The force is halved and the object's mass is doubled?

An object accelerates at 4.1 m/s² under the action of two rubber bands.What will be the object's acceleration if it is pulled by four rubber bands?