# Homework Help: Help I dunno how to use coefficient

1. Oct 2, 2008

### theLHC

Help... I dunno how to use coefficient!!!

1. The problem statement, all variables and given/known data
A 20 kg mass is moving along a horizontal surface. A 150 N force is applied to it. If the coefficient of kinetic friction is 0.10, calculate
a) The force of friction
b)The net force
c)The acceleration
Draw a force diagram

3. The attempt at a solution

Well, I don't know how to calculate a-c, but I attempted to draw a force diagram of it:

Since I cannot post it, i will describe how it looks:
A block is on the surface of the floor. It has a force of 200 N pushing down on the ground, and the push of 150 N pushing the object. The resulting force is 240 N, if measured by scale diagram. Thats about as far as I got. Please help...

2. Oct 2, 2008

### LowlyPion

Re: Help... I dunno how to use coefficient!!!

The coefficient of friction will apply to the force between the block and the surface. And this would have a relationship with the 200N downward force. But it's effect would serve to retard the 150N horizontal force.

3. Oct 2, 2008

### theLHC

Re: Help... I dunno how to use coefficient!!!

well how can you put this into a summation equation?
where does the friction coefficient go into the equation?

4. Oct 2, 2008

### LowlyPion

Re: Help... I dunno how to use coefficient!!!

What is the frictional force? Is it easier to drag a wooden box of books over the carpet or over an ice rink surface?

If the coefficient of friction applies to its downward force, what direction does it act.

5. Oct 2, 2008

### theLHC

Re: Help... I dunno how to use coefficient!!!

well, i guess it acts in the downward direction???

6. Oct 2, 2008