An electric toy car with a mass of $2 k g$ $2 kg$ is powered by a motor with a voltage of $3 V$ $3 V$ and a current supply of $7 A$ $7 A$ . How long will it take for the toy car to accelerate from rest to $\frac{3}{2} \frac{m}{s}$ $3/2 m/s$ ?

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An electric toy car with a mass of $2 k g$ $2 kg$ is powered by a motor with a voltage of $3 V$ $3 V$ and a current supply of $7 A$ $7 A$ . How long will it take for the toy car to accelerate from rest to $\frac{3}{2} \frac{m}{s}$ $3/2 m/s$ ?

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Answer 1 · 2017-07-17T05:46:09

The time is $= 0.11 s$ $=0.11s$

Explanation:

The power is

$P = U I$ $P=UI$

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

The current is $I = 7 A$ $I=7A$

The power is

$P = U I = 3 \cdot 7 = 21 W$ $P=UI=3*7=21W$

The kinetic energy of the car is

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

The mass is $m = 2 k g$ $m=2kg$

The speed is $v = \frac{3}{2} m s^{- 1}$ $v=3/2ms^-1$

so,

$E = \frac{1}{2} \cdot 2 \cdot {(\frac{3}{2})}^{2} = 2.25 J$ $E=1/2*2*(3/2)^2=2.25J$

Let the time $= t s$ $=ts$

$E = P t$ $E=Pt$

$t = \frac{E}{P} = \frac{2.25}{21} = 0.11 s$ $t=E/P=2.25/21=0.11s$

Answer 2 · 2017-07-17T05:46:23

t= 0,107 s

Explanation:

the final kinetic energy of the car is $E_{K} = \frac{1}{2} m v^{2} = \frac{1}{2} 2 k g \times {(1, 5 \frac{m}{s})}^{2} = 2, 25 J$ $E_K = 1/2 mv^2 = 1/2 2 kg xx (1,5 m/s)^2= 2,25 J$
the power supplied is $P = V \times I = 3 V \times 7 A = 21 W$ $P= V xx I=3 V xx 7A = 21 W$
since P=E/t you have $t = \frac{E}{P} = \frac{2, 25 J}{21 W} = 0, 107 s$ $t = E/P = (2,25J)/ (21 W) = 0,107 s$

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An electric toy car with a mass of $2 k g$ $2 kg$ is powered by a motor with a voltage of $3 V$ $3 V$ and a current supply of $7 A$ $7 A$ . How long will it take for the toy car to accelerate from rest to $\frac{3}{2} \frac{m}{s}$ $3/2 m/s$ ?

2 Answers

Explanation:

Explanation:

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An electric toy car with a mass of 2 kg2kg2 kg is powered by a motor with a voltage of 3 V3V3 V and a current supply of 7 A7A7 A. How long will it take for the toy car to accelerate from rest to 3/2 m/s32ms3/2 m/s?

2 Answers

Explanation:

Explanation:

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An electric toy car with a mass of $2 k g$ $2 kg$ is powered by a motor with a voltage of $3 V$ $3 V$ and a current supply of $7 A$ $7 A$ . How long will it take for the toy car to accelerate from rest to $\frac{3}{2} \frac{m}{s}$ $3/2 m/s$ ?