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 $1 A$ . How long will it take for the toy car to accelerate from rest to $5/3 m/s$ ?

Question

1502 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2017-03-05T16:14:37

$0.6s$

Electrical power is

$P=IV$

and mechanical power is

$P = E/t$

so

$E/t = IV$

We can work out $E$ by

$E = 1/2mv^2 = 1/2 xx 3 xx (5/3)^2 = 4.17J$

Rearrange the equation for time, which we want to find:

$t = E/(IV) = 4.17/(7xx1) = 0.6s$

An electric toy car with a mass of 3 kg3 kg is powered by a motor with a voltage of 7 V7 V and a current supply of 1 A1 A. How long will it take for the toy car to accelerate from rest to 5/3 m/s5/3 m/s?