An electric toy car with a mass of $3 k g$ $3 kg$ is powered by a motor with a voltage of $8 V$ $8 V$ and a current supply of $11 A$ $11 A$ . How long will it take for the toy car to accelerate from rest to $7 \frac{m}{s}$ $7 m/s$ ?

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Answer 1 · 2017-03-24T07:09:24

The time is $= 0.84 s$ $=0.84s$

Voltage is $U = 8 V$ $U=8V$

Current is $I = 11 A$ $I=11A$

The power is

$P = U I = 8 \cdot 11 = 88 W$ $P=UI=8*11=88W$

Velocity is $v = 7 m s^{- 1}$ $v=7ms^-1$

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

The kinetic energy is

$K E = \frac{1}{2} m v^{2} = \frac{1}{2} \cdot 3 \cdot 7^{2} = 73.5 J$ $KE=1/2mv^2=1/2*3*7^2=73.5J$

But,

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

$t = \frac{E}{P} = \frac{73.5}{88} = 0.84 s$ $t=E/P=73.5/88=0.84s$

An electric toy car with a mass of 3kg3 kg is powered by a motor with a voltage of 8V8 V and a current supply of 11A11 A. How long will it take for the toy car to accelerate from rest to 7ms7 m/s?