- #1

raptik

- 21

- 0

## Homework Statement

A puck of mass m = 1.10 kg slides in a circle of radius r = 18.0 cm on a frictionless table while attached to a hanging cylinder of mass M = 3.00 kg by a cord through a hole in the table. What speed (in m/s) keeps the cylinder at rest?

## Homework Equations

F = ma

## The Attempt at a Solution

I know the F

_{net,y}for the hanging cylinder is zero because it does not move, so I deduced that T - F

_{g}= 0.

On the puck the 2 things I looked at was the a moving towards the hole and the tension which I am also deducing is moving towards the hole, away from the puck. (Note: I left out F

_{N}and F

_{g}because I didn't see how they would apply in the equation for the puck.) I thus got the equation T = ma.

I then plugged in the in this T into the previous equation to get: ma - F

_{g}= 0

I then simplified the equation to a = g. Knowing that a in circular motion with constant velocity is a = v

^{2}/R, so the equation I ended up with was v = √Rg. This came out to 1.328 ms

^{-1}, which is wrong. Could somebody tell me where my thinking went astray and how I can fix this.