An electric toy car with a mass of $3 kg$ is powered by a motor with a voltage of $2 V$ and a current supply of $3 A$ . How long will it take for the toy car to accelerate from rest to $3/2 m/s$ ?

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Answer 1 · 2018-01-08T14:04:14

The time is $=0.5625s$

The power is

$P=UI$

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

The voltage is $U=2V$

The current is $I=3A$

The power is

$P=UI=2*3=6W$

The kinetic energy of the car is

$E=1/2mv^2$

The mass of the car is $m=3kg$

The speed is $v=3/2ms^-1$

So,

The kinetic energy is

$E=1/2mv^2=1/2*3*(3/2)^2=27/8J$

Let the time $=(t)s$

$E=Pt$

$"Energy=Power" xx "time"$

The time is

$t=E/P=(27/8)/6=0.5625s$

An electric toy car with a mass of 3 kg3 kg is powered by a motor with a voltage of 2 V2 V and a current supply of 3 A3 A. How long will it take for the toy car to accelerate from rest to 3/2 m/s3/2 m/s?