# Homework Help: Kinetic energy

1. Jan 2, 2008

### kirstynl

okay, i tried searching knietic energy and it wont come up,
soooo here's a questions:

a force of 40 N continues to push a 5 kg box and acclerates it a .70 m/s/s what is the coefficient of friction/

i got the static because it wasn't movingm, but i have no idiea how to get that please help

2. Jan 2, 2008

### Shooting Star

First, tell us what was the net force acting on the body.

3. Jan 2, 2008

### HallsofIvy

This problem has nothing to do with kinetic energy! As shooting star said (I seem to spending the day right behind him!), it is entirely a matter of force. What is the net force on the body? Also I have no idea what you mean by "I got the static because it wasn't moving". What wasn't moving? What "static"?

4. Jan 3, 2008

### Shooting Star

Do you by chance mean you "get" the case for static friction? Anyway, reply to our questions if you want to understand the problem.

5. Jan 3, 2008

### will.c

if the acceleration is .7 m/s^2, and the box has a mass of five kilograms, Newton will only take a second to tell you the net force on the box.

Of course, if there's a difference between the applied force and the net force, there must be another force acting on the box. This is where you'll find your kinetic friction.