# Atwood's Machine. I am asked to solve for the unknown mass.

1. Jul 8, 2015

### Ocata

1. The problem statement, all variables and given/known data

Given m_1 on an Atwood's Machine, what is the mass of m_2?

2. Relevant equations

$a_{net1} = \frac{m_{1}-m_{2}}{m_{1}+m_{2}}g$

3. The attempt at a solution

$a_{net1} = \frac{m_{1}-x}{m_{1}+x}g$

$\frac{a}{g} = \frac { m_{1} - x } { m_{1}+x }$

$\frac {a}{g}m_{1} + \frac{a}{g}x - m_{1} = -x$

$x = \frac { \frac{a}{g}(m_{1}) - m_{1} } {- \frac{a}{g} - 1}$

Is this correct?

2. Jul 8, 2015

### Orodruin

Staff Emeritus
Assuming that you know the acceleration of m1, yes. Please write down the full question in future posts.

3. Jul 8, 2015

### Ocata

Hi Orodruin,

This was a lab assignment, the full question was something like: Determine the mass of a block that is attached to one side of a pulley, using lab measurements. I'm assuming that I would have measured the acceleration and based on m1 and the acceleration, solve for m2.