AP Physics Friction

When looking at friction problems, if the net force in the x-direction on an object is zero, what can we say about its acceleration?

• it is positive

• it is negative

• it is zero

• not enough information is given

Tags

NGSS.MS-PS2-2

What direction does friction act relative to sliding?

• in the same direction

• in the opposite direction 

• need more information

• depends on the force

What is the force of friction between a block of ice that weighs 950 N and the ground if μ = .12?

• 65 N

• 226 N

• 175 N

• 114 N

Tags

NGSS.MS-PS2-2

A box takes 40 N to start moving when the coefficient of static friction is .54. What is the weight of the box? 

• 81 N

• 18 N

• 98 N

• 74 N

Tags

NGSS.MS-PS2-2

Normal force is

• Always opposite the weight

• Always parallel and down the incline

• Always perpendicular to the surface

• It depends on the direction of motion

Which of the following is the best expression for the Normal Force?

• F_N = mg cos(ϴ)

• F_N = mg sin(ϴ)

• F_N = mg sin(180-ϴ)

• F_N = mg cos(90-ϴ)

Tags

NGSS.MS-PS2-2

A box weighing 46 newtons rests on an incline that makes an angle of 25° with the horizontal. What is the magnitude of the component of the box’s weight perpendicular to the incline?

• 19N

• 21N

• 42N

• 26N

A cart rolls down an inclined plane with constant speed as shown in the diagram below. Which arrow represents the direction of frictional force?

• A

• B

• C

• D

Tags

NGSS.MS-PS2-1

NGSS.MS-PS2-2

A 10.-newton block is sliding down a 30-degree incline at a constant speed. What is the force of friction?

• 5N

• 4.9N

• 10N

• 98N

Tags

NGSS.MS-PS2-2

A 1.0 × 10⁵-newton truck at rest on a hill that makes an angle of 8.0° with the horizontal. What is the component of the truck’s weight parallel to the hill?

• 1.4E3N

• 1E4N

• 1.4E4N

• 9.9E4N

Tags

NGSS.MS-PS2-4