Solving Mike's Crate Motion After 2 Secs

[cheerspens]

Homework Statement

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?

Homework Equations

F_NET=ma

The Attempt at a Solution

I used F_NET=ma to solve for the acceleration as follows:
F_PC-F_FC=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.

 

[calef]

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.

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)

 

[cheerspens]

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

 

[calef]

Exactly.