# physics

posted by
**Morgan**
.

I;m sorry, but I was stuck on the second part of this problem. Can you please help me?

An automobile engine slows down from 4500 rpm to 1500 rpm in 2.5 seconds.

a) calculate angular accceleration

b)calculate total number of revolutions done in this time.

What I did:

a) I got the answer, and it was right, and it was also negative, but: what confused me was b

b) It is decelerating, this really confused me. I wasn't even sure how to approach this.