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 $5 A$ . How long will it take for the toy car to accelerate from rest to $4 m/s$ ?

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Answer 1 · 2017-04-14T06:13:43

The time is $=0.69s$

Voltage is $U=7V$

Current is $I=5A$

The power is

$P=UI=7*5=35W$

Velocity is $v=4ms^-1$

Mass is $m=3kg$

The kinetic energy is

$KE=1/2mv^2=1/2*3*(4)^2=24J$

But,

$E=P*t$

The time is $t=E/P=(24)/35=0.69s$

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 5 A5 A. How long will it take for the toy car to accelerate from rest to 4 m/s4 m/s?