An electric toy car with a mass of 3 kg is powered by a motor with a voltage of 7 V and a current supply of 5 A. How long will it take for the toy car to accelerate from rest to 2 m/s?

1 Answer
Apr 17, 2017

The time is =0.17s

Explanation:

Voltage is U=7V

Current is I=5A

The power is

P=UI=7*5=35W

Velocity is v=2ms^-1

Mass is m=3kg

The kinetic energy is

KE=1/2mv^2=1/2*3*(2)^2=6J

But,

E=P*t

The time is t=E/P=(6)/35=0.17s