# Force Problem

1. Apr 14, 2010

### cheerspens

1. The problem statement, all variables and given/known data
Mike is dragging a 20.0 kg crate across the floor. If he exerts 40 N force upon the crate and there is a 25 N frictional force opposing the crate's motion, how fast will the crate be moving after 2.0 seconds if it is initially at rest?

2. Relevant equations
FNET=ma

3. The attempt at a solution
I used FNET=ma to solve for the acceleration as follows:
FPC-FFC=ma
40-25=20a
15=20a
a=0.75m/s2

Then here's where I'm not sure if this is correct: I multiplied the acceleration 0.75m/s2 by 2.0 seconds to get 1.5m/s2.
Is this the correct answer for the question: How fast will the crate be moving after 2.0 seconds?
Thanks.

2. Apr 14, 2010

### calef

Almost right. What happens when you multiply an acceleration by a time? What are the units? (You have the correct numeric answer, your units are off)

3. Apr 14, 2010

### cheerspens

Oh it wouldn't be squared. So it would be 1.5m/s.

4. Apr 14, 2010

Exactly.