Calculating Velocity After a Force is Applied

[cheerspens]

Homework Statement

Jennifer applies a force of 2.0 N upon a 100.0 kg wagon, which was initially moving at 0.50 m/s. This force acts over a distance of 5.0 m. Assume friction can be neglected.
a) What is the wagon's velocity after Jennifer's push if she pushes the wagon in the direction of motion?
b) What is the wagon's velocity after Jennifer's push if her push opposes the wagon's motion?

Homework Equations

KE=.5v²
lw-l=F\DeltaXcos\theta
w+=F\DeltaXcos\theta

The Attempt at a Solution

a) I got an initial KE of 12.5 J and an initial IE of 10 J. My ending KE was 22.55 J. My answer was a velocity of 0.67 m/s. Is this correct?

b) I got and initial KE of 12.5 J then my ending IE was -10 J and ending KE 2.55 J. My answer for the velocity was 0.23 m/s. Is this correct?

Thanks!

 

[PhanthomJay]

As in your other post, you are getting correct answers, but refrain from using the term 'internal energy' when work done by non conservative forces are involved. Instead , use work energy methods...in part a, for example, the work done by the applied force is 10J, don't call it internal energy. What equation are you using when you refer to 'internal energy'?