# HW help

1. Feb 8, 2005

### HurricaneH

Any help will be aprreciated...

1. A car traveling on a flat circular track accelerates uniformly from rest with a tangential acceleration of 1.70 m/s2. The car makes it one quarter of the way around the circle before skidding off the track. Determine the coefficient of static friction between car and track.

2. Three particles are connected by rigid rods of negligible mass lyuing around the y axis. (y=3, y=-2, y=-4). If the system rotates about the x axis with an angular speed of 2 rad/s, find (a) the moment of inertia about the x axis and the total rotationaly energy evaluated from 1/2Iw2 and (b) the linear speed of each particle and the total energy evaluated from (sigma)1/2mivi^2.

Just point me in the right direction....

2. Feb 8, 2005

### dextercioby

1.The friction force is a centripetal force.Equate the work done by the 2 forces & extract µ.
2.This is simple.What ideas do u have for it...?

Daniel.

3. Feb 8, 2005

### HurricaneH

forgot the weights...

y=3m, 4kg, y=-2m, 2kg, y=-4m, 3kg

I= (4)(3)^2 + (2)(2)^2 + (3)(4)^2
I= 92kg

4. Feb 8, 2005

RE= 1/2Iw^2

1/2(92)(2)^s

(46)(4)

184 J....

5. Feb 8, 2005

### dextercioby

Yes,it's okay.Basically your problem's done. The last point is as easy as it was the first.

Daniel.