Question 1

A crate is sliding down an inclined ramp at a constant speed of 0.55 m/s.The vector sum of all the forces acting on this crate must point down the ramp.

Accepted Answer

If the crate is moving at a constant speed, the net force on the crate must be zero. Since the crate is sliding down an inclined ramp, there must be a component of the force of gravity acting down the ramp and a component of the normal force acting perpendicular to the ramp. Therefore, the vector sum of all the forces acting on the crate must be equal to zero, not necessarily pointing down the ramp.

Question 2

A dog is standing in the bed of a pickup truck.The bed is coated with ice,causing the force of friction between the dog and the truck to be zero.The truck is initially at rest,and then accelerates to the right,moving along a flat road.As seen from a stationary observer (watching the truck move to the right),the dog
A) does not move left or right, but the back of the truck moves towards the dog.
B) moves to the right, but not as quickly as the truck is moving to the right, causing it to slide towards the back of the truck.
C) moves to the right at the same rate as the truck, so it doesn't slide.
D) moves to the left, as the truck moves to the right, causing the dog to slide towards the back of the truck.

Accepted Answer

Since there is no friction between the dog and the truck bed, the dog remains stationary relative to the ground as the truck accelerates to the right. This makes it appear as if the back of the truck moves towards the dog from the perspective of a stationary observer.

Question 3

Two bodies P and Q on a smooth horizontal surface are connected by a light cord.The mass of P is greater than that of Q.A horizontal force  (of magnitudeF) is applied to Q as shown in the figure, accelerating the bodies to the right. The magnitude of the force exerted by the connecting cord on body P will be

A) zero.
B) less than F but not zero.
C) equal to F.
D) greater than F.

Accepted Answer

Since the cord is light, it can be assumed to be taut at all times.
Therefore, the tension in the cord is equal to the force exerted by body Q on the cord, which is F.
Since the bodies are connected, they will have the same acceleration.
Thus, the net force on body P is (its weight - tension in cord), which is greater than zero.
Therefore, the force exerted by the connecting cord on body P is less than F but not zero.

Question 4

A block lies on a horizontal frictionless surface. A horizontal force of 100 N is applied to the block giving rise to an acceleration of 3.0 m/s². (a) Determine the mass of the block. (b) Calculate the distance the block will travel if the force is applied for 10 s. (c) Calculate the speed of the block after the force has been applied for 10 s.

Accepted Answer

The answer of A block lies on a horizontal frictionless...

Question 5

A ball is tossed vertically upward.When it reaches its highest point (before falling back downward)
A) the velocity is zero, the acceleration is directed downward, and the force of gravity acting on the ball is directed downward.
B) the velocity is zero, the acceleration is zero, and the force of gravity acting on the ball is zero.
C) the velocity is zero, the acceleration is zero, and the force of gravity acting on the ball is directed downward.
D) the velocity and acceleration reverse direction, but the force of gravity on the ball remains downward.
E) the velocity, acceleration, and the force of gravity on the ball all reverse direction.

Accepted Answer

At the highest point of its trajectory, a ball's velocity is zero because it stops for an instant before falling back down. However, acceleration due to gravity remains directed downward at approximately 9.8 m/s^2, and the force of gravity also continues to act downward on the ball. This is because gravity is a constant force acting on objects near Earth's surface, influencing their acceleration regardless of their momentary state of motion.

Question 6

Two unequal masses M and m (M > m)are connected by a light cord passing over a pulley of negligible mass,as shown in the figure.When released,the system accelerates.Friction is negligible.Which figure below gives the correct free-body force diagrams for the two masses in the moving system? 
A)

B)

C)

D)

Accepted Answer

The answer of Two unequal masses M and m (M...

Question 7

Suppose you are playing hockey on a new-age ice surface for which there is no friction between the ice and the hockey puck.You wind up and hit the puck as hard as you can.After the puck loses contact with your stick,the puck will
A) start to slow down.
B) not slow down or speed up.
C) speed up a little, and then slow down.
D) speed up a little, and then move at a constant speed.

Accepted Answer

Since there is no friction between the ice and the puck, there are no external forces acting on the puck. According to Newton's first law of motion, the puck will continue to move at a constant velocity unless acted upon by an external force. Therefore, the puck will not slow down or speed up after leaving the stick.

Question 8

A woman is straining to lift a large crate,without success because it is too heavy.We denote the forces on the crate as follows: P is the upward force the woman exerts on the crate,C is the vertical contact force exerted on the crate by the floor,and W is the weight of the crate.How are the magnitudes of these forces related while the woman is trying unsuccessfully to lift the crate?
A) P + C = W
B) P + C < W
C) P + C > W
D) P = C

Accepted Answer

P + C = W. When the woman is trying to lift the crate but is unsuccessful, the crate does not move, indicating it is in static equilibrium. Therefore, the sum of the upward forces (P + C) must equal the downward force (W) due to gravity.

Question 9

Which of the graphs in the figure represents a spring that gets less stiff the more it is stretched? 
A) Graph a
B) Graph b
C) Graph c
D) Graph d

Accepted Answer

The answer of Which of the graphs in the figure...

Question 10

A small car has a head-on collision with a large truck.Which of the following statements concerning the magnitude of the average force due to the collision is correct?
A) The truck experiences the greater average force.
B) The small car experiences the greater average force.
C) The small car and the truck experience the same average force.
D) It is impossible to tell since the masses are not given.
E) It is impossible to tell since the velocities are not given.

Accepted Answer

According to Newton's third law of motion, for every action, there is an equal and opposite reaction. This means that the magnitude of the force on the truck is equal to the magnitude of the force on the small car during the collision.

Question 11

An object is moving forward with a constant velocity.Which statement about this object MUST be true?
A) The net force on the object is zero.
B) The net force on the object is in the forward direction.
C) No forces are acting on the object.
D) The acceleration of the object is in the forward direction.

Accepted Answer

If an object is moving forward with a constant velocity, that means it is not accelerating. In order for an object to accelerate, there must be a net force acting on it. Therefore, if the object is not accelerating, the net force on it must be zero as stated in choice A. Choices B and D are not necessarily true because the object can have a net force and still be moving with a constant velocity if the forces are balanced. Choice C is also not necessarily true because an object can have forces acting on it and still have a constant velocity if the forces are balanced.

Question 12

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 A) 3.0 m/s². B) 2.2 m/s². C) 1.0 m/s². D) We cannot tell from the information given.

Accepted Answer

The answer of If a 5.0 kg box is pulled...

Question 13

A 7.0-kg object is acted on by two forces. One of the forces is 10.0 N acting toward the east. Which of the following forces is the other force if the acceleration of the object is 1.0 m/s² toward the east? A) 6.0 N east B) 3.0 N west C) 12 N east D) 9.0 N west E) 7.0 N west

Accepted Answer

The answer of A 7.0-kg object is acted on by...

Question 14

You are seated in a bus and notice that a hand strap that is hanging from the ceiling hangs away from the vertical in the backward direction.From this observation,you can conclude that
A) the velocity of the bus is forward.
B) the velocity of the bus is backward.
C) You cannot conclude anything about the direction of the velocity of the bus.

Accepted Answer

The answer of You are seated in a bus and...

Question 15

Which of the graphs in the figure illustrates Hooke's Law? 
A) Graph a
B) Graph b
C) Graph c
D) Graph d

Accepted Answer

The answer of Which of the graphs in the figure...

Question 16

The figure shows an acceleration-versus-force graph for three objects pulled by rubber bands.The mass of object 2 is 36 kg.What are the masses of objects 1 and 3? 
A) 14 kg and 90 kg
B) 72 kg and 18 kg
C) 90 kg and 18 kg
D) 14 kg and 72 kg

Accepted Answer

The answer of The figure shows an acceleration-versus-force graph for...

Question 17

A box slides down a frictionless plane inclined at an angle θ above the horizontal.The gravitational force on the box is directed
A) parallel to the plane in the same direction as the movement of the box.
B) parallel to the plane in the opposite direction as the movement of the box.
C) perpendicular to the plane.
D) vertically.
E) at an angle θ below the inclined plane.

Accepted Answer

The gravitational force on the box is always vertically downwards, as gravity always acts vertically downwards. The force parallel to the plane causing the box to slide down is a component of the gravitational force.

Question 18

Consider two less-than-desirable options.In the first you are driving 30 mph and crash head-on into an identical car also going 30 mph.In the second option you are driving 30 mph and crash head-on into a stationary brick wall.In neither case does your car bounce off the thing it hits,and the collision time is the same in both cases.Which of these two situations would result in the greatest impact force?
A) hitting the other car
B) hitting the brick wall
C) The force would be the same in both cases.
D) We cannot answer this question without more information.
E) None of these is true.

Accepted Answer

The force experienced in both scenarios would be the same because the change in velocity and collision time are the same, according to Newton's third law of motion.

Question 19

Two objects having masses m₁ and m₂ are connected to each other as shown in the figure and are released from rest.There is no friction on the table surface or in the pulley.The masses of the pulley and the string connecting the objects are completely negligible.What must be true about the tension T in the string just after the objects are released? A) T = m₂g B) T > m₂g C) T < m₂g D) T = m₁g E) T > m₁g

Accepted Answer

The answer of Two objects having masses m₁ and m₂...

Question 20

Consider a plot of the displacement (x)as a function of the applied force (F)for an ideal elastic spring.The slope of the curve would be
A) the spring constant.
B) the reciprocal of the spring constant.
C) the acceleration due to gravity.
D) the reciprocal of the acceleration of gravity.
E) the mass of the object attached to the spring.

Accepted Answer

The slope of the displacement vs. applied force plot for an ideal elastic spring is the reciprocal of the spring constant, according to Hooke's Law (F = kx), where k is the spring constant.

Quiz 1: A: Foundations

A crate is sliding down an inclined ramp at a constant speed of 0.55 m/s.The vector sum of all the forces acting on this crate must point down the ramp.

A ball is tossed vertically upward.When it reaches its highest point (before falling back downward)

Two unequal masses M and m (M > m) are connected by a light cord passing over a pulley of negligible mass,as shown in the figure.When released,the system accelerates.Friction is negligible.Which figure below gives the correct free-body force diagrams for the two masses in the moving system?

Suppose you are playing hockey on a new-age ice surface for which there is no friction between the ice and the hockey puck.You wind up and hit the puck as hard as you can.After the puck loses contact with your stick,the puck will

Which of the graphs in the figure represents a spring that gets less stiff the more it is stretched?

A small car has a head-on collision with a large truck.Which of the following statements concerning the magnitude of the average force due to the collision is correct?

An object is moving forward with a constant velocity.Which statement about this object MUST be true?

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

A 7.0-kg object is acted on by two forces. One of the forces is 10.0 N acting toward the east. Which of the following forces is the other force if the acceleration of the object is 1.0 m/s² toward the east?

You are seated in a bus and notice that a hand strap that is hanging from the ceiling hangs away from the vertical in the backward direction.From this observation,you can conclude that

Which of the graphs in the figure illustrates Hooke's Law?

The figure shows an acceleration-versus-force graph for three objects pulled by rubber bands.The mass of object 2 is 36 kg.What are the masses of objects 1 and 3?

A box slides down a frictionless plane inclined at an angle θ above the horizontal.The gravitational force on the box is directed

Consider a plot of the displacement (x) as a function of the applied force (F) for an ideal elastic spring.The slope of the curve would be

Quiz 1: A: Foundations

A crate is sliding down an inclined ramp at a constant speed of 0.55 m/s.The vector sum of all the forces acting on this crate must point down the ramp.

A ball is tossed vertically upward.When it reaches its highest point (before falling back downward)

Two unequal masses M and m (M > m) are connected by a light cord passing over a pulley of negligible mass,as shown in the figure.When released,the system accelerates.Friction is negligible.Which figure below gives the correct free-body force diagrams for the two masses in the moving system?

Suppose you are playing hockey on a new-age ice surface for which there is no friction between the ice and the hockey puck.You wind up and hit the puck as hard as you can.After the puck loses contact with your stick,the puck will

Which of the graphs in the figure represents a spring that gets less stiff the more it is stretched?

A small car has a head-on collision with a large truck.Which of the following statements concerning the magnitude of the average force due to the collision is correct?

An object is moving forward with a constant velocity.Which statement about this object MUST be true?

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

A 7.0-kg object is acted on by two forces. One of the forces is 10.0 N acting toward the east. Which of the following forces is the other force if the acceleration of the object is 1.0 m/s2 toward the east?

You are seated in a bus and notice that a hand strap that is hanging from the ceiling hangs away from the vertical in the backward direction.From this observation,you can conclude that

Which of the graphs in the figure illustrates Hooke's Law?

The figure shows an acceleration-versus-force graph for three objects pulled by rubber bands.The mass of object 2 is 36 kg.What are the masses of objects 1 and 3?

A box slides down a frictionless plane inclined at an angle θ above the horizontal.The gravitational force on the box is directed

Consider a plot of the displacement (x) as a function of the applied force (F) for an ideal elastic spring.The slope of the curve would be

A 7.0-kg object is acted on by two forces. One of the forces is 10.0 N acting toward the east. Which of the following forces is the other force if the acceleration of the object is 1.0 m/s² toward the east?