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Question 1:

Which type of friction acts on an object that is not moving?

A) Static friction
B) Kinetic friction
C) Rolling friction
D) Fluid friction

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Explanation: The correct answer is A) Static friction. Static friction is the frictional force that prevents an object from moving when a force is applied to it. It acts in the opposite direction of the applied force and adjusts its magnitude to match the force applied, up to a maximum value known as the maximum static friction.

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Question 2:

Which type of friction acts on an object that is in motion?

A) Static friction
B) Kinetic friction
C) Rolling friction
D) Fluid friction

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Explanation: The correct answer is B) Kinetic friction. Kinetic friction is the frictional force that acts on an object that is in motion. It opposes the relative motion between the object and the surface it is in contact with. The magnitude of kinetic friction is generally less than the maximum static friction.

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Question 3:

Which type of friction is generally greater in magnitude: static friction or kinetic friction?

A) Static friction
B) Kinetic friction
C) They are generally equal in magnitude
D) It depends on the nature of the surfaces in contact

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Explanation: The correct answer is A) Static friction. In general, static friction is greater in magnitude than kinetic friction. Static friction can vary its magnitude up to the maximum static friction to match the applied force and prevent the object from moving. Kinetic friction, on the other hand, acts on a moving object and generally has a lower magnitude.

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Question 4:

Which factor does not affect the magnitude of static friction between two surfaces?

A) The normal force between the surfaces
B) The nature of the surfaces
C) The relative velocity between the surfaces
D) The roughness of the surfaces

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Explanation: The correct answer is C) The relative velocity between the surfaces. The magnitude of static friction depends on factors such as the normal force, the nature ofthe surfaces, and the roughness of the surfaces. However, the relative velocity between the surfaces does not affect the magnitude of static friction. Static friction only comes into play when the object is on the verge of moving, and the relative velocity is zero in that case.

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Question 5:

Which type of friction is generally greater: kinetic friction or rolling friction?

A) Kinetic friction
B) Rolling friction
C) They can be equal in magnitude
D) It depends on the nature of the surfaces in contact

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Explanation: The correct answer is B) Rolling friction. Rolling friction, which occurs when an object rolls over a surface, is generally less than kinetic friction. Rolling friction is influenced by factors such as the nature of the surfaces in contact, the shape of the object, and the presence of lubrication. In many cases, rolling friction can be significantly smaller than kinetic friction, making rolling more efficient than sliding.