# Homework Help: Finding the number of revolutions for an car in an angular system

1. Nov 2, 2008

### tyro008

1. The problem statement, all variables and given/known data

The angular speed of an automobile engine is increased at a constant rate from 1500 rev/min to 3900 rev/min in 14 s.
(A) What is its angular acceleration in revolutions per minute-squared?

(B) How many revolutions does the engine make during this 14 s interval?

2. Relevant equations
I found out (A) to be 10285.71429 rev/min^2, but I have no idea how to do (B). would have to find tangential velocity or do i have enough information already?

3. The attempt at a solution
for (A), i used the formula $$\alpha$$ = $$\Delta$$$$\omega$$ / time
so (3900rev/min - 1500rev/min)/14,
and this was 10285.71420rev/min^2
i just don't know how to start (B)..

2. Nov 2, 2008

### tyro008

oh sorry, the alpha stands for angular acceleration
the delta of little omega stands for change in anuglar speed :]

3. Nov 2, 2008

### tyro008

whoops, change in angular* speed