Solving for Revolutions: Electric-Generator Turbine

[rjimenez]

Homework Statement

An electric-generator turbine spins at 3600rpm . Friction is so small that it takes the turbine 16.0 min to coast to a stop.How many revolutions does it make while stopping?

Homework Equations

The Attempt at a Solution

(3600rev/min)(16.0min)=57600 i tried this and know the answer is wrong

 

[G01]

You have to remember that in order for the turbine to come to a stop, it has to be slowing down. In other words, the turbine must have some angular acceleration in order to slow down to a stop. The fact that the angular acceleration is not zero makes the formula you used invalid. Do you know what the angular acceleration is? If you do, what relationships involving the angular acceleration can you use to find the total amount of revolutions after 16 minutes?