An electric toy car with a mass of $3 k g$ $3 kg$ is powered by a motor with a voltage of $4 V$ $4 V$ and a current supply of $1 A$ $1 A$ . How long will it take for the toy car to accelerate from rest to $4 \frac{m}{s^{2}}$ $4 m/s^2$ ?

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Answer 1 · 2017-06-10T09:31:34

The time is $= 6 s$ $=6s$

Voltage is $U = 4 V$ $U=4V$

Current is $I = 1 A$ $I=1A$

The power of the motor is

$P = U I = 4 \cdot 1 = 4 W$ $P=UI=4*1=4W$

Velocity is $v = 4 m s^{- 1}$ $v=4ms^-1$

Mass is $m = 3 k g$ $m=3kg$

The kinetic energy of the car is

$K E = \frac{1}{2} m v^{2} = \frac{1}{2} \cdot 3 \cdot {(4)}^{2} = 24 J$ $KE=1/2mv^2=1/2*3*(4)^2=24J$

But,

$E = P \cdot t$ $E=P*t$

The time is $t = \frac{24}{4} = 6 s$ $t=(24)/4=6s$

An electric toy car with a mass of 3kg3 kg is powered by a motor with a voltage of 4V4 V and a current supply of 1A1 A. How long will it take for the toy car to accelerate from rest to 4ms24 m/s^2?