- #1

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## Homework Statement

A block of mass M has a string of mass m attached to it. A force F is applied to the string and it pulls the block up a frictionless plane that is inclined at an angle theta. Find the force that the string exerts on the block

## Homework Equations

F=ma

## The Attempt at a Solution

Force of the string on the block = Force of the block on the string = N

Force applied to string = F

acceleration of block = acceleration of string = a[/B]

**My first equation was the net-force equation for the string:**

ma = -mg*sin(theta) - N + F

ma = -mg*sin(theta) - N + F

**My second equation was the net-force equation for the block:**

Ma = -Mg*sin(theta) + N

Ma = -Mg*sin(theta) + N

**solving for the acceleration in the top equation and plugging it into the second equation gives the following (after a small amount of algebra)**

**N = (F/m)*(1+M/m)^-1**

**Which is not the answer I am supposed to be getting. I am guessing the problem is with my net-force equations but I can't located a specific problem. Anyone want to explain what I'm doing wrong here?**