Question

An electric toy car with a mass of `5 kg` is powered by a motor with a voltage of `12 V` and a current supply of `1 A`. How long will it take for the toy car to accelerate from rest to `3 m/s`?

Answer 1

`t=1.875s`

Explanation:

let the time taken be t s
Then electrical energy spent during this time `V*I*t`
Rhis energy will be equal to the KE gained=`1/2mv^2`

`V*I*t=1/2*m*v^2`
`12*1*t=1/2*5*3^2`
`t=45/24=15/8=1.875s`