# Homework Help: 2 masses on a pulley

1. Apr 8, 2010

### lockedup

1. The problem statement, all variables and given/known data
A mass $$m_{1}$$ is hanging from a light cord which is strung over a pulley of moment of inertia, I, and radius $$R_{0}$$ and connected to a mass $$m_{2}$$ which is sliding on a rough horizontal surface with coefficient of friction $$\mu_{k}$$.

a) What is the acceleration of the system?
b) What are the tensions in each part of the cord?

All help is appreciated! :)

2. Relevant equations
$$\Sigma$$F = ma
$$\Sigma\tau$$ = m$$R^{2}\alpha$$

3. The attempt at a solution
I started by trying to sum up all the forces and torques but I don't know where to go from there.

$$\Sigma F_{x} = T - \mu m_{1}g = (\mu m_{1} + m_{2})g = ma$$
$$\Sigma F_{y} = T = m_{2}g$$
$$\Sigma \tau = rF_{x} + rF_{y}$$
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Apr 8, 2010

### ideasrule

Always start by drawing a free-body diagram on each object, including the pulley, and writing out Newton's second law for each object.