Frictional Force

What is the formula to calculate the force of friction?

• force of friction = coefficient of friction * normal force

• force of friction = mass * acceleration

• force of friction = velocity * time

• force of friction = weight * distance

Which diagram represents balanced forces?

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Friction is greater when surfaces are

• rougher

• smoother

• smaller

• taller

For two surfaces in contact, which is greater

• coefficient of static friction

• coefficient of kinetic friction

The frictional force acting against stationary objects is

• static friction

• kinetic friction

The frictional force acting against objects in motion is

• static friction

• kinetic friction

A 9 kg chair sits at rest on a concrete floor. If the coefficient of static friction between the chair and floor is .25, how much force will it take to set the chair in motion?

• 22 N

• 2.25 N

• .23 N

• 88.3 N

You can reduce friction by

• reducing surface area
• removing lubricant
• increasing mass

What type of force is the RED arrow indicating?

• Applied force

• Tension

• Spring

• Friction

What is the type of force that both the ground and the wall exerts on the sitting man?

• Friction

• Gravity

• Applied Force

• Normal Force