Mini-Quiz: Coefficient of Rolling Friction

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

   It is proportional to the radius of the wheelSorry, not correct. Try another button. The coefficient is the radius of the wheelGood try, but not right. Select another answer. It is inversely proportional to the radius of the wheelThat is correct. You are becoming a Champion in rolling friction.

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

   Apply torque on the wheel until it spinsSorry, not correct. Try another button. Measure the normal force or weight of the wheelOops! Wrong answer. Re-read the question and try again. Start a wheel rolling and measure the time it takes to stopCorrect. You sure are smart!

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

   The train wheel, because it moves slowerGood try, but not right. Select another answer. The automobile tire, because rubber is softer than steelThat is correct. You are becoming a Champion in rolling friction. Neither has rolling friction; instead they only have sliding frictionOops! Wrong answer. Re-read the question and try again.

Pick an answer to see instant feedback. Re-read the lesson if you miss one.