# Mini-Quiz: Coefficient of Rolling Friction

by Ron Kurtus (20 November 2016)

Take this Mini-Quiz to check your understanding of the lesson material.

1. How is the coefficient of rolling friction related to the radius of the wheel?

It is proportional to the radius of the wheel

The coefficient is the radius of the wheel

It is inversely proportional to the radius of the wheel

2. What is one way to measure the coefficient of rolling friction?

Apply torque on the wheel until it spins

Measure the normal force or weight of the wheel

Start a wheel rolling and measure the time it takes to stop

3. Which has a greater coefficient of rolling friction, a steel train wheel or an automobile tire?

The train wheel, because it moves slower

The automobile tire, because rubber is softer than steel

Neither has rolling friction; instead they only have sliding friction

If you got all three correct, you are on your way to becoming a Champion in Physics. If you had problems, you had better look over the material again.

Smile and be happy

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