An electric toy car with a mass of $5 kg$ is powered by a motor with a voltage of $6 V$ and a current supply of $12 A$ . How long will it take for the toy car to accelerate from rest to $7 m/s$ ?

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Answer 1 · 2018-01-05T06:23:20

The time is $=0.24s$

The power is

$P=UI$

$"Power"="Voltage"xx"Current"$

The voltage is $U=6V$

The current is $I=12A$

The power is

$P=UI=6*12=72W$

The kinetic energy of the car is

$E=1/2mv^2$

The mass of the car is $m=5kg$

The speed is $v=7ms^-1$

so,

$E=1/2*5*(7)^2=35/2J$

Let the time $=(t)s$

$E=Pt$

$"Energy=Power" xx "time"$

The time is

$t=E/P=(35/2)/72=0.24s$

An electric toy car with a mass of 5 kg5 kg is powered by a motor with a voltage of 6 V6 V and a current supply of 12 A12 A. How long will it take for the toy car to accelerate from rest to 7 m/s7 m/s?