An electric toy car with a mass of $4 kg$ is powered by a motor with a voltage of $2 V$ and a current supply of $7 A$ . How long will it take for the toy car to accelerate from rest to $8 m/s$ ?

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Answer 1 · 2017-05-09T10:11:09

The time is $=9.14s$

Voltage is $U=2V$

Current is $I=7A$

The power of the motor is

$P=UI=2*7=14W$

Velocity is $v=8ms^-1$

Mass is $m=4kg$

The kinetic energy of the car is

$KE=1/2mv^2=1/2*4*(8)^2=128J$

But,

$E=P*t$

The time is $t=128/14=9.14s$

An electric toy car with a mass of 4 kg4 kg is powered by a motor with a voltage of 2 V2 V and a current supply of 7 A7 A. How long will it take for the toy car to accelerate from rest to 8 m/s8 m/s?