# Worksheet: Circular Motion Problems

In this worksheet, we will practice applying rotational kinematics and centripetal dynamics to problems in various situations.

**Q4: **

A car takes a 100.0-m-radius banked curve at angle. If the car takes a banked curve at less than the ideal speed, friction is needed to keep it from sliding toward the inside of the curve (a problem on icy mountain roads).

Calculate the ideal speed for the car to take the curve.

What is the minimum coefficient of friction needed for a frightened driver to take the curve at 20.0 km/h?

**Q6: **

A child with mass 40 kg sits on the edge of a merry-go-round at a distance of 3.0 m from its axis of rotation. The merry-go-round accelerates from rest to 0.40 rev/s in 10 s. The coefficient of static friction between the child and the surface of the merry-go-round is 0.60. After the merry-go-round has accelerated for 5.0 seconds, by how much does the frictional force on the child exceed the force accelerating her due to the merry-go-round’s rotation?