An electric toy car with a mass of 15 kg is powered by a motor with a voltage of 8 V and a current supply of 3 A. How long will it take for the toy car to accelerate from rest to 4 m/s?

1 Answer
Mar 5, 2017

t=5s

Explanation:

Electrical power is given by

P=IV

and mechanical power by

P = E/t

so

E/t = IV

We can calculate the kinetic energy, E, by

E = 1/2mv^2 = 1/2 xx 15 xx 4^2 = 120J

The question is asking about time, so

t = E/(IV) = 120/(8xx3) = 5s