# Newton's Laws of Motion Question

1. Oct 8, 2014

### I <3 Physic

1. The problem statement, all variables and given/known data
A cart of mass 1.5 kg is connected by a string over a pulley to a hanging mass of 300g. What would be the acceleration of the cart and mass if the force of gravity is approximately 1N for a 100g mass.
Cart 1=1.5kg
Cart 2=0.3 Kg
Fg1=15N
Fg2=3N

2. Relevant equations

F=ma
3. The attempt at a solution
So im having a bit of difficulty picturing this problem in my mind but here is my solution. I need to find the variables F,M, and a. So F would be 15-3=12N because the cart 1 needs to overpower the 3N in order to move it up. The weight would be 1.5kg so i would plug that into the equation to get 12/1.5=8m/s^2(Down). I could do the other one as well 12/0.3=40m/s^2. I was wondering if this is correct?

2. Oct 8, 2014

### Staff: Mentor

Hi I <3 Physic, Welcome to Physics Forums.

The problem setup is a cart on a level surface (like a table top) connected by a string which goes over a pulley to some mass that's hanging from the string. So only one of the masses involved is subject to the force of gravity affecting the tension in the string.

You'll want to draw free body diagrams (FBDs) for both objects. The string remains taught with some tension T acting on both objects. You should be able to use the FBD to write expressions for the acceleration of both of them with the tension T as a shared variable (the tension in the string is the same for both objects).