An electric toy car with a mass of $8 kg$ is powered by a motor with a voltage of $9 V$ and a current supply of $4 A$ . How long will it take for the toy car to accelerate from rest to $8/3 m/s$ ?

Question

1446 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2017-03-05T15:20:53

$0.79s$

The kinetic energy into the car is given by

$E = 1/2mv^2 = 1/2 xx 8 xx (8/3)^2 = 28.4J$

The power from an electric circuit is given by

$P = IV$

Mechanical power, meanwhile, is

$P = E/t$

so

$IV = E/t$

The question is asking for $t$ , so

$t = E/(IV)$

and, plugging in values that we know,

$t = 28.4/(9xx4) = 0.79s$

An electric toy car with a mass of 8 kg8 kg is powered by a motor with a voltage of 9 V9 V and a current supply of 4 A4 A. How long will it take for the toy car to accelerate from rest to 8/3 m/s8/3 m/s?