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 $3 A$ $3 A$ . How long will it take for the toy car to accelerate from rest to $4 \frac{m}{s}$ $4 m/s$ ?

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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 $3 A$ $3 A$ . How long will it take for the toy car to accelerate from rest to $4 \frac{m}{s}$ $4 m/s$ ?

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Answer 1 · 2017-02-22T08:01:25

The time is 1 second.

Explanation:

Given:
$m a s s = 3 kg$ $mass = 3" kg"$
$V_{motor} = 8 Volts$ $V_"motor" = 8" Volts"$
$I_{motor} = 3 Amperes$ $I_"motor" = 3" Amperes"$
$V e l o c i t y = 4 m/s$ $Velocity = 4" m/s"$

Let t = the time of acceleration.
Let $P =$ $P =$ the power of motor $= (V_{motor}) (I_{motor})$ $= (V_"motor")(I_"motor")$

The energy provided by the motor is:

$E_{motor} = P t$ $E_"motor" = Pt$

The kinetic energy of the vehicle:

$E_{kinetic} = \frac{1}{2} m a s s {(V e l o c i t y)}^{2}$ $E_"kinetic" = 1/2mass(Velocity)^2$

The following step assumes no loss in the system:

$E_{motor} = E_{kinetic}$ $E_"motor" = E_"kinetic"$

$P t = \frac{1}{2} m a s s {(V e l o c i t y)}^{2}$ $Pt = 1/2mass(Velocity)^2$

$t = \frac{m a s s {(V e l o c i t y)}^{2}}{2 P}$ $t = (mass(Velocity)^2)/(2P)$

$t = \frac{3 kg {(4 m/s)}^{2}}{2 (8 Volts) (3 Amperes)}$ $t = (3" kg"(4" m/s")^2)/(2(8" Volts")(3" Amperes")$

$t = \frac{3 kg (16 m^{2} {/s}^{2})}{2 (24 Watts)}$ $t = (3" kg"(16" m"^2"/s"^2))/(2(24" Watts")$

$t = 1 s$ $t = 1" s"$

Answer 2 · 2017-02-22T08:06:42

The time is $= 1 s$ $=1s$

Explanation:

The power is

$P = U I$ $P=UI$

$U = 8 V$ $U=8V$

$I = 3 A$ $I=3A$

$P = 3 \cdot 8 = 24 W$ $P=3*8=24W$

The change in kinetic energy is

$DeltaKE=1/2mv^2-1/2m u^2$

$u=0$

$v=4ms^-1$

$m=3kg$

$DeltaKE=1/2*3*16-0$

$=24J$

But

$P=(DeltaKE)/t$

So,

$t=(DeltaKE)/P$

$=24/24=1s$

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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 $3 A$ $3 A$ . How long will it take for the toy car to accelerate from rest to $4 \frac{m}{s}$ $4 m/s$ ?

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Explanation:

Explanation:

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Science

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An electric toy car with a mass of 3 kg3kg3 kg is powered by a motor with a voltage of 8 V8V8 V and a current supply of 3 A3A3 A. How long will it take for the toy car to accelerate from rest to 4 m/s4ms4 m/s?

2 Answers

Explanation:

Explanation:

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Impact of this question

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 $3 A$ $3 A$ . How long will it take for the toy car to accelerate from rest to $4 \frac{m}{s}$ $4 m/s$ ?