An electric toy car with a mass of $5 k g$ $5 kg$ is powered by a motor with a voltage of $12 V$ $12 V$ and a current supply of $8 A$ $8 A$ . How long will it take for the toy car to accelerate from rest to $3 \frac{m}{s}$ $3 m/s$ ?

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Answer 1 · 2017-03-29T13:37:46

The time is $= 0.23 s$ $=0.23s$

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

Current is $I = 8 A$ $I=8A$

The power is

$P = U I = 12 \cdot 8 = 96 W$ $P=UI=12*8=96W$

Velocity is $v = 3 m s^{- 1}$ $v=3ms^-1$

Mass is $m = 5 k g$ $m=5kg$

The kinetic energy is

$K E = \frac{1}{2} m v^{2} = \frac{1}{2} \cdot 5 \cdot 3^{2} = 22.5 J$ $KE=1/2mv^2=1/2*5*3^2=22.5J$

But,

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

The time is $t = \frac{E}{P} = \frac{22.5}{96} = 0.23 s$ $t=E/P=22.5/96=0.23s$

An electric toy car with a mass of 5kg5 kg is powered by a motor with a voltage of 12V12 V and a current supply of 8A8 A. How long will it take for the toy car to accelerate from rest to 3ms3 m/s?