# Homework Help: Non-uniform circular motion (i think)

1. Oct 13, 2006

### bigredd87

I guess I need to find a tangential acceleration or something and and velocity at which the tube breaks and also a time it takes to get to that velocity, but I'm not sure. Can anybody help please?

A 600 g steel block rotates on a steel table while attached to a 1.20 m-long hollow tube. Compressed air fed through the tube and ejected from a nozzle on the back of the block exerts a thrust force of 4.81 N perpendicular to the tube. The maximum tension the tube can withstand without breaking is 60.0 N. If the block starts from rest, how many revolutions does the block complete before the tube breaks?

2. Oct 13, 2006

### civil_dude

Do you have a picture? In what plane is this rotating? What exactly does the nozzle do?

3. Oct 13, 2006

### bigredd87

well i guess since it is a steel table it is rotating along the tangential axis, and here is the pic that i have. this pic along with what the problem is all the info I have. I also think that u have kinetic friction, so if that is the case, then the coefficient for steel on steel without lubrication is 0.6 (according to my physics book) so u can maybe use that.

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Last edited: Oct 13, 2006
4. Oct 13, 2006

### Staff: Mentor

You need to do two things:
(1) Determine the speed that requires the tube to exert a force equal to its breaking strength. Hint: Centripetal acceleration.
(2) Determine the tangential acceleration and use it to figure out how long it takes to get to the breaking speed.