Problem 53P

A certain car can accelerate from rest to the speed v in T seconds. If the power output of the car remains constant, (a) how long does it take for the car to accelerate from v to 2v? (b) How fast is the car moving at 2T seconds after starting?

Solution 53P

a.)

Step 1 of 4

We have to find how long it takes for a car to accelerate from to , if it can accelerate from rest to the speed in seconds.

The car starts from rest so the kinetic energy at some later instant of time is given by

Now, the power output of the car at later instant is given by

and

(Work done is equal to change in kinetic energy)

Hence,