An electric toy car with a mass of $5 k g$ $5 kg$ 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 $2 \frac{m}{s}$ $2 m/s$ ?

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Answer 1 · 2018-04-30T12:02:00

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

The power is

$P = U I$ $P=UI$

$Power = Voltage \times Current$ $"Power"="Voltage"xx"Current"$

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 of the car is $m = 5 k g$ $m=5kg$

The speed is $v = 2 m s^{- 1}$ $v=2ms^-1$

So,

The kinetic energy is

$E = \frac{1}{2} m v^{2} = \frac{1}{2} \cdot 5 \cdot {(2)}^{2} = 10 J$ $E=1/2mv^2=1/2*5*(2)^2=10J$

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

$E = P t$ $E=Pt$

$Energy=Power \times time$ $"Energy=Power" xx "time"$

The time is

$t = \frac{E}{P} = \frac{10}{12} = 0.83 s$ $t=E/P=(10)/12=0.83s$

An electric toy car with a mass of 5kg5 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 2ms2 m/s?