- #1

JamesEarl

- 9

- 0

## Homework Statement

The figure below shows two boxes, m1 and m2. m1 = 10 kg is sitting on a frictionless horizontal surface, while m2 = 7 kg is hanging vertically. The two masses are connected by a massless string that is wrapped around a massless, frictionless pulley.

Figure: http://class.phys.psu.edu/WebAssign_figures/two-box connected.jpg

What is the acceleration of m1?

What is the tension in the string?

m1= 10kg

m2= 7kg

## Homework Equations

ax=m2g/(m1+m2)

## The Attempt at a Solution

So I got the right answer for acceleration, which was 4.04 m/s2. However, I've already made two attempts at the tension and both were wrong. I tried looking at it from two different standpoints. After drawing a free body diagram, it looks like T=m1ax. When I plug in the numbers, I get 40.4, which is incorrect. I then tried looking at it from the other block. T=m2(9.8-ax). The answer for this was the same, and therefore incorrect. I then tried -40.4, which was also wrong. Anyone have any ideas? The only hunch I have is that the tensions offset, making the answer 0. However, this really doesn't make any sense because there has to be some tension in the rope.

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