Friction and Forces Quiz

What is the primary difference between static and kinetic friction?

• Static friction acts when surfaces are moving, while kinetic friction acts when surfaces are stationary.

• Static friction is greater than kinetic friction.

• Kinetic friction is always zero.

• Kinetic friction acts before motion begins.

Which of the following is true about the coefficient of friction (μ)?

• The coefficient of static friction is always less than the coefficient of kinetic friction.

• The coefficient of friction is the same for all material pairs.

• The coefficient of friction is a dimensionless number that depends on the materials in contact.

• The coefficient of friction is always greater than 1.

Which equation represents the static friction force?

• Fs = μk x Fn

• Fs = μs x Fn

• Fs = μs + Fn

• Fs = Fn / μk

Once an object starts moving, the force of friction that acts on it is:

• Static friction

• Rolling friction

• Kinetic friction

• No friction acts once the object is moving

In the video, what factor does NOT significantly affect the frictional force between two surfaces?

• The roughness of the surfaces

• The normal force

• The area of contact between the surfaces

• The type of materials in contact