# Rotational motion problem

1. Apr 5, 2005

### imnotsmart

A 50.0 kg child stands at the rim of a merry-go-round of radius 1.90 m rotating with an angular speed of 3.00 rad/s.
(a) What is the child's centripetal acceleration?
(b)What is the minimum force between her feet and the floor of the merry-go-round that is required to keep her in the circular path?
(c) What minimum coefficient of static friction is required?

Need some help getting started. Don't really know where to go here?

Last edited: Apr 5, 2005
2. Apr 5, 2005

### whozum

a)
$$v_{linear} = \omega r$$

That should give you a velocity, along with radius you can find acceleration.

b) You know that the only force keeping her in circular motion is the centripetal force, and the only forces acting are friction and gravity. Does gravity alone help her stay in circular motion? If not, how does friction do the job?

c) This is just number crunching after you figure out the equation in (b)