# Newtons 3rd Law

1. Dec 2, 2009

### slobodan48

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

Two masses are places in a frictionless pulley system. Solve for the acceleration and tension force. )its a pullz question and the mu=0.1

2. Relevant equations
So i know that Fg=MG
Fnet=ma
Ff=MFn
How can i solve this question? how come Fnet=Ft came out of nowhere?

3. The attempt at a solution

2. Dec 2, 2009

### Cryxic

This seems to be an Atwood machine problem, although I don't understand the last part of the problem statement.

You will want to set up the equations of motion for each mass. For mass m(1):

F1 = m(1)*a = T -m(1)*g = 0

For m(2):

F2 = m(2)*a = m(2)*g - T = 0

To solve for tension, first solve the two equations for acceleration (a) and then set them equal to each other. Then solve for T. For acceleration, solve the equation for T and set them equal to each other. Then solve for a.

3. Dec 2, 2009

### slobodan48

well the mu is 0.1 and i dont know were did you get the m and t-m

4. Dec 2, 2009

### Cryxic

Here's where I'm getting confused. What is mu?

5. Dec 2, 2009

### slobodan48

well it looks like a U,its the coefficent of friction, its grade 11 physics

6. Dec 2, 2009

### Cryxic

But you said the system was frictionless.

7. Dec 2, 2009

### slobodan48

shoot, my bad i was looking at the wrong question. sorry