# Homework Help: Coefficient of friction homework problem

1. Nov 7, 2007

### copyfilew

1. The problem statement, all variables and given/known data
A 10kg mass is released from rest and slides down an incline that makes an angle of 37degrees with the horizontal. The coefficient of friction is 0.4 on the incline. Determine (a) the force of friction acting to oppose the motion, and (b) the acceleration

2. Relevant equations
Determine (a) the force of friction acting to oppose the motion, and (b) the acceleration

3. The attempt at a solution

I first drew a free body diagram...

N = (m)(g)Cos(37)
N = 75

F = (0.4)(75)
= 30

Is that correct?

2. Nov 7, 2007

### Chi Meson

yes, correct so far. Find a.

3. Nov 7, 2007

### pooface

I am getting normal force as 78.35 N

4. Nov 7, 2007

### Chi Meson

I agree with pooface. And that's the first time I have ever said that sentence! 78 N is better.

5. Nov 7, 2007

### copyfilew

To be honest, I have no idea where to go from here. Any hints?

6. Nov 7, 2007

### pooface

calculate the force acting down the slope. then you would the friction acting one way and the force the other way.

Subtract them and get the net force. Then you can use F=ma to find acceleration.