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3 years ago

5

A 1430 kg car speeds up from 7.50 m/s to 11.0 m/s in 9.30 s. Ignoring friction, how much power did that require?(unit=W)PLEASE H

ELP

1 answer:

AlexFokin [52]3 years ago

7 0

Answer:

4982.8 W

Explanation:

Given the mass of the car = 1430 kg

initial speed = 7.5m/sec

final speed = 11.0 m/sec

time = 9.30sec

Assuming constant accelration a We know that

v=u+at

11=7.5+9.3a

a=0.376 $m/sec^2$

We know that F=ma

F= $1430*0.376 = 538.2N$

We know that $v^2-u^2=2as$

$11^2-7.5^2=2*0.376*s$

s= 86.10m

We know that work(W)= $F*s$

W= $538.2*86.10$ = 46339.02J = 46.34KJ

We know that power= $\frac{work}{time}$ = $\frac{46.34}{9.3}=4.982$ KW

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An American traveler in China carries a transformer to convert China's standard 220 V to 120 V so that she can use some small ap

Arisa [49]

Answer:

(a) The ratio of turns in the primary and secondary coils of her transformer is 1.833

(b) The ratio of input to output current is 0.55

(c) To increase the output voltage, you can either increase the number of turns in the secondary coil (step-up) or increase the input current. Therefore, the Chinese person has to increase the input current of the transformer to achieve an increased output voltage that can power her 220 V appliances.

Explanation:

Given;

input voltage, $V_p$ = 220 V

output voltage, $V_s$ = 120 V

General transformer equation is given as;

$\frac{V_p}{V_s} = \frac{N_p}{N_s} = \frac{I_s}{I_p}$

where;

Np is number of turns in the primary coil

Ns is number of turns in the secondary coil

Is - is the secondary current or output current

Ip - is the primary current or input current

(a) The ratio of turns in the primary and secondary coils of her transformer;

$\frac{N_p}{N_s} = \frac{V_p}{V_s} \\\\\frac{N_p}{N_s} = \frac{220}{120} = 1.833$

(b) The ratio of input to output current;

$\frac{I_p}{I_s} = \frac{V_s}{V_p} \\\\\frac{I_p}{I_s} = \frac{120}{220} \\\\\frac{I_p}{I_s} = 0.55$

(c) To increase the output voltage, you can either increase the number of turns in the secondary coil (step-up) or increase the input current. Therefore, the Chinese person has to increase the input current of the transformer to achieve an increased output voltage that can power her 220 V appliances.

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2 years ago

Calculate the phase angle (in radians) for a circuit with a maximum voltage of 12 V and w-50 Hz. The voltage source is connected

Vinvika [58]

Answer:

The phase angle is 0.0180 rad.

(c) is correct option.

Explanation:

Given that,

Voltage = 12 V

Angular velocity = 50 Hz

Capacitance $C= 20\times10^{-2}\ F$

Inductance $L=20\times10^{-3}\ H$

Resistance $R= 50\ Omega$

We need to calculate the impedance

Using formula of impedance

$z=\sqrt{R^2+(\omega L-\dfrac{1}{\omega C})^2}$

$z=\sqrt{50^2+(50\times20\times10^{-3}-\dfrac{1}{50\times20\times10^{-2}})^2}$

$z=50.00$

We need to calculate the phase angle

Using formula of phase angle

$\theta=\cos^{-1}(\dfrac{R}{z})$

$\theta=\cos^{-1}(\dfrac{50}{50.00})$

$\theta=0.0180\ rad$

Hence, The phase angle is 0.0180 rad.

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3 years ago

What is the kinetic energy of a 200 kg satellite as it follows a circular orbit of radius 8x106m around the earth?

motikmotik

Given the equation for the Speed of a Satellite

v = SqRt{Gravitational Constant}{Mass of Earth} divided by the radius given in your problem

we have:

(square root whole term on right side)

v = G Me
———
r

so. (6.67x10^-11)(5.97x10^24)
___________________
(8.0x10^6)

v = 7055 m/s (which is reasonable)

so utilize the Kinetic Energy Formula

KE = 1/2mv^2

KE = 1/2(200)(7055)^2

KE = 4.977x10^9 J

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Answer:

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