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 `8 A`. How long will it take for the toy car to accelerate from rest to `3 m/s`?

Answer 1

The time is `=0.23s`

Explanation:

Voltage is `U=12V`

Current is `I=8A`

The power is

`P=UI=12*8=96W`

Velocity is `v=3ms^-1`

Mass is `m=5kg`

The kinetic energy is

`KE=1/2mv^2=1/2*5*3^2=22.5J`

But,

`E=P*t`

The time is `t=E/P=22.5/96=0.23s`