An electric toy car with a mass of $5 kg$ is powered by a motor with a voltage of $8 V$ and a current supply of $7 A$ . How long will it take for the toy car to accelerate from rest to $7 m/s$ ?

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Answer 1 · 2017-06-26T13:23:43

The time is $=2.2s$

The voltage is $U=8V$

The current is $I=7A$

The power of the motor is

$P=UI=8*7=56W$

Velocity is $v=7ms^-1$

Mass is $m=5kg$

The kinetic energy of the car is

$KE=1/2mv^2=1/2*5*(7)^2=122.5J$

But,

$E=P*t$

The time is $t=(122.5)/56=2.2s$

An electric toy car with a mass of 5 kg5 kg is powered by a motor with a voltage of 8 V8 V and a current supply of 7 A7 A. How long will it take for the toy car to accelerate from rest to 7 m/s7 m/s?