AP Physics Week 9 Practice

A truck traveling to the right with

constant speed carries a box in its rear.

The driver suddenly applies the brakes

and the truck slows to a stop. The instant

that the brakes are applied, the box slides

toward the front of the truck. What force

is responsible for the box sliding toward

the front of the truck?

• Weight

• Inertia

• Friction Force

• There is no force that caused the box to slide foward.

Tags

NGSS.HS-PS2-1

A car with good tires travels up a hill

with constant speed. Let W represent the

weight, N represent the normal force, and

f represent the static friction force acting

on the car. Any other external force on

the car is labeled F. Which of the

following diagrams correctly shows the

forces acting on the car as it travels up the

hill?

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NGSS.HS-PS2-1

A known mass hangs from a

force sensor inside of an

elevator. As the elevator

moves from the bottom floor

to the roof-level of a

building, the upward force

acting on the mass is

recorded as a function of

time in the graph shown.

Which of the following

questions could NOT be

answered by the data in the

graph and the known mass?

• What is the acceleration of the elevator as it leaves the ground floor?

• What is the maximum speed attained by the elevator?

• What is the approximate height of the building?

• All of these questions could be answered by these data.

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NGSS.HS-PS2-1

The diagrams below show three situations in which one or more blocks are set on a frictionless track. The frictionless track has an inclined section and a horizontal section. A pulley wheel separates these two sections. In Case 1, a 1 kg block is set at rest on the inclined section. Upon release, the 1 kg block has an acceleration of 6 m/s2. In Case 2, a 2 kg block is set on the inclined section and released from rest. What acceleration will the 2 kg block have as it slides down the incline?

• 2 m/s²

• 3 m/s²

• 4 m/s²

• 6 m/s²

Tags

NGSS.HS-PS2-1

The diagrams below show three situations in which one or more blocks are set on a frictionless track. The frictionless track has an inclined section and a horizontal section. A pulley wheel separates these two sections. In Case 1, a 1 kg block is set at rest on the inclined section. Upon release, the 1 kg block has an acceleration of 6 m/s2. In Case 3, the 2 kg block is connected to the 1 kg block by a string. The 2 kg block rests on the horizontal section, the 1 kg block is held fixed on the inclined section, and the string passes over the

ideal pulley. What acceleration will the system of blocks have the instant that the 1 kg block is released?

• 2 m/s²

• 3 m/s²

• 4 m/s²

• 6 m/s²

Tags

NGSS.HS-PS2-1

Block A is attached to Block B, which is attached to a rope that is being pulled with constant force. There is a very light force sensor between the blocks that is oriented to measure the constant tension force on Block A in this case. The student wishes to verify Newton’s Third Law. Which of the

following should the student also do in order to gather appropriate data to verify Newton’s Third Law?

• Change the orientation of the force sensor.

• Apply the same force on Block A in the opposite direction.

• Switch Blocks A and B in the experimental setup.

• Replace the rope with a spring.

A student attempts to explain how a car accelerates forward by saying that “the car’s engine exerts a forward force on the car.” This statement is

• True, because a car without a working engine cannot accelerate forward.

• True, because the engine exerts a force on the car’s wheels, making them turn.

• False, because the engine is not in direct contant with the wheels of the car.

• False, because a net force on the car must come from an object or system that is

  outside of the car.

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NGSS.HS-PS2-1

A block of mass m1 is initially at rest on top of a block of mass m2, also at rest. There is noticeable friction between the blocks, but not between m2 and the table. In case 1, a force F is applied to m1, causing both blocks to accelerate and also slip against each other. In case 2, the same force F is instead applied to mass m2, which again causes both blocks to accelerate and slip against each other. In which case does the acceleration of the m1-m2 center of mass have greater magnitude?

• Case 1

• Case 2

• Both the same

• Depends on which mass is greater

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NGSS.HS-PS2-1

Two correct answers:

Three forces of equal magnitude act on the box shown. One

force is upward, one downward, and one rightward. Which of the following statements must be true based on this

information? Select two answers.

• The box must have a rightward component of velocity.

• The box has no vertical component of velocity.

• The acceleration of the box is directed to the right.

• The velocity of the box is changing with time.

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NGSS.HS-PS2-1

A block slides from rest down a frictionless quarter-circular incline as shown. Which of the following graphs represents the block’s acceleration due to gravity as a function of time while the block is on the quarter-circle?

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NGSS.HS-PS2-1