Question

An electric toy car with a mass of `4 kg` is powered by a motor with a voltage of `12 V` and a current supply of `5 A`. How long will it take for the toy car to accelerate from rest to `5 m/s`?

Answer 1

The time is `=0.83s`

Explanation:

Voltage is `U=12V`

Current is `I=5A`

The power is

`P=UI=12*5=60W`

Velocity is `v=5ms^-1`

Mass is `m=4kg`

The kinetic energy is

`KE=1/2mv^2=1/2*4*(5)^2=50J`

But,

`E=P*t`

The time is `t=E/P=(50)/60=0.83s`