AP Physics 1: Algebra-Based Practice Quiz: Kinetic and Static Friction
Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026
Test your understanding with short quizzes. This quiz has 16 questions to check your progress.
Question 1 of 16
All Questions (16)
A) When two surfaces in contact are at rest relative to each other.
B) When two surfaces in contact move relative to each other.
C) Only when an object is accelerating.
D) Only when an object is at rest on an incline.
Correct Answer: B
The content explicitly states that 'Kinetic friction occurs when two surfaces in contact move relative to each other.'
A) The friction between two surfaces that are moving at a constant velocity.
B) The friction that occurs when an object starts to slide.
C) The friction that may occur between the contacting surfaces of two objects that are not moving relative to each other.
D) The product of the normal force and the coefficient of kinetic friction.
Correct Answer: C
The content states, 'Static friction may occur between the contacting surfaces of two objects that are not moving relative to each other.'
A) By multiplying the coefficient of static friction by the object's mass.
B) By multiplying the normal force by the coefficient of kinetic friction.
C) By finding the force required to keep an object stationary.
D) By dividing the normal force by the coefficient of kinetic friction.
Correct Answer: B
The content specifies that 'The magnitude of the kinetic friction force exerted on an object is the product of the normal force the surface exerts on the object and the coefficient of kinetic friction.'
A) It has a constant value for any given pair of surfaces.
B) It is always greater than the applied force.
C) It adopts the value and direction required to prevent an object from slipping.
D) It is always equal to the product of the normal force and the coefficient of static friction.
Correct Answer: C
The content states that 'Static friction adopts the value and direction required to prevent an object from slipping or sliding on a surface.' This means it is a variable force up to a certain maximum.
A) The coefficient of static friction is typically smaller.
B) The coefficient of static friction is typically greater.
C) The coefficients are always equal.
D) The relationship depends on the speed of the object.
Correct Answer: B
As stated in the provided content, 'The coefficient of static friction is typically greater than the coefficient of kinetic friction for a given pair of surfaces.'
A) Kinetic friction
B) Static friction
C) Both kinetic and static friction
D) No friction
Correct Answer: B
Since the crate is not moving relative to the floor, the friction preventing the motion is static friction, as described in the content.
A) The force of static friction, which is equal to the applied force.
B) The force of kinetic friction, which is the product of the normal force and the coefficient of kinetic friction.
C) The force of static friction, which is at its maximum value.
D) The force of kinetic friction, which is greater than the maximum static friction.
Correct Answer: B
The object is moving, so kinetic friction applies. The content defines the magnitude of this force as the product of the normal force and the coefficient of kinetic friction.
A) Greater than 10 N.
B) Less than 10 N.
C) Exactly 10 N.
D) It cannot be determined without the coefficient of static friction.
Correct Answer: C
The content states that static friction 'adopts the value and direction required to prevent an object from slipping.' Since the desk is not moving, the static friction force must be equal in magnitude and opposite in direction to the applied force of 10 N.
A) It takes more force to start an object sliding than to keep it sliding.
B) Friction is independent of the surface area in contact.
C) Heavier objects always experience more friction.
D) An object will accelerate once it starts to slide.
Correct Answer: A
Because the coefficient of static friction is greater, the maximum static friction force (the force needed to start motion) is greater than the kinetic friction force (the force needed to be overcome to maintain motion).
A) Mass and the coefficient of kinetic friction.
B) Normal force and the coefficient of static friction.
C) Normal force and the coefficient of kinetic friction.
D) Applied force and the coefficient of kinetic friction.
Correct Answer: C
This is a direct application of the rule provided: 'The magnitude of the kinetic friction force... is the product of the normal force... and the coefficient of kinetic friction.'
A) It can act on any type of surface.
B) Its magnitude is always constant.
C) It changes its magnitude to match the net applied force, up to a maximum limit.
D) It can switch between being kinetic and static friction instantaneously.
Correct Answer: C
The description that static friction 'adopts the value and direction required to prevent an object from slipping' implies that its magnitude changes to counteract any applied force, as long as that force doesn't exceed the maximum possible static friction.
A) A car's tires push on the road to accelerate it (static friction), while a skidding car's tires slide on the road (kinetic friction).
B) A box at rest on a ramp experiences kinetic friction, while a sliding box experiences static friction.
C) Static friction is the force on a falling object, while kinetic friction is the force on a rolling object.
D) Kinetic friction prevents motion, while static friction opposes motion.
Correct Answer: A
This option correctly applies the definitions. For a non-skidding tire, the contact point with the road is not moving relative to the road, so it's static friction. For a skidding tire, the surfaces are moving relative to each other, so it's kinetic friction.
A) The surfaces must be moving at a constant velocity.
B) The surfaces must be accelerating.
C) The surfaces must not be moving relative to each other.
D) The surfaces must be perfectly smooth.
Correct Answer: C
The content explicitly states that static friction may occur between the contacting surfaces of two objects 'that are not moving relative to each other.'
A) It remains the same.
B) It is halved.
C) It is doubled.
D) It becomes zero.
Correct Answer: C
Because static friction 'adopts the value... required to prevent an object from slipping,' it must be equal and opposite to the applied force. If the applied force is doubled (and the block still doesn't move), the static friction force must also double to maintain equilibrium.
A) It is the friction between two surfaces at rest.
B) Its magnitude depends on the applied force needed to keep an object stationary.
C) It is the friction between two surfaces in contact that are in relative motion.
D) It is typically stronger than the maximum static friction.
Correct Answer: C
This is the core definition provided in the content: 'Kinetic friction occurs when two surfaces in contact move relative to each other.'
A) The force of static friction has a variable magnitude.
B) The force of kinetic friction acts on objects that are sliding.
C) The coefficient of kinetic friction is generally larger than the coefficient of static friction.
D) An object at rest on a surface may experience a static friction force.
Correct Answer: C
The content explicitly states the opposite: 'The coefficient of static friction is typically greater than the coefficient of kinetic friction for a given pair of surfaces.' Therefore, this statement is incorrect.