An electric toy car with a mass of $4 k g$ $4 kg$ is powered by a motor with a voltage of $12 V$ $12 V$ and a current supply of $5 A$ $5 A$ . How long will it take for the toy car to accelerate from rest to $5 \frac{m}{s}$ $5 m/s$ ?

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Answer 1 · 2017-04-29T05:39:15

The time is $= 0.83 s$ $=0.83s$

Voltage is $U = 12 V$ $U=12V$

Current is $I = 5 A$ $I=5A$

The power is

$P = U I = 12 \cdot 5 = 60 W$ $P=UI=12*5=60W$

Velocity is $v = 5 m s^{- 1}$ $v=5ms^-1$

Mass is $m = 4 k g$ $m=4kg$

The kinetic energy is

$K E = \frac{1}{2} m v^{2} = \frac{1}{2} \cdot 4 \cdot {(5)}^{2} = 50 J$ $KE=1/2mv^2=1/2*4*(5)^2=50J$

But,

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

The time is $t = \frac{E}{P} = \frac{50}{60} = 0.83 s$ $t=E/P=(50)/60=0.83s$

An electric toy car with a mass of 4kg4 kg is powered by a motor with a voltage of 12V12 V and a current supply of 5A5 A. How long will it take for the toy car to accelerate from rest to 5ms5 m/s?