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

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Answer 1 · 2017-12-05T07:01:46

The time is $= 0.125 s$ $=0.125s$

The power is

$P = U I$ $P=UI$

The voltage is $U = 3 V$ $U=3V$

The current is $I = 4 A$ $I=4A$

The power is

$P = U I = 3 \cdot 4 = 12 W$ $P=UI=3*4=12W$

The kinetic energy of the car is

$E = \frac{1}{2} m v^{2}$ $E=1/2mv^2$

The mass is $m = 3 k g$ $m=3kg$

The speed is $v = 1 m s^{- 1}$ $v=1ms^-1$

so,

$E = \frac{1}{2} \cdot 3 \cdot {(1)}^{2} = 1.5 J$ $E=1/2*3*(1)^2=1.5J$

Let the time $= (t) s$ $=(t)s$

$E = P t$ $E=Pt$

$t = \frac{E}{P} = \frac{1.5}{12} = 0.125 s$ $t=E/P=(1.5)/12=0.125s$

An electric toy car with a mass of 3kg3 kg is powered by a motor with a voltage of 3V3 V and a current supply of 4A4 A. How long will it take for the toy car to accelerate from rest to 1ms1 m/s?