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3 years ago

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An escalator is 18.3 m long. If a person stands on the escalator, it takes 47.8 s to ride from the bottom to the top. If a perso

n walks up the moving escalator with a speed of 0.521 m/s relative to the escalator, how long does it take the person to get to the top?

1 answer:

Novay_Z [31]3 years ago

8 0

Answer:

20.243 s

Explanation:

Because the escalator and person moving in the same direction, relative velocity can be calculated by summing the velocity of the escalator and velocity of the person.

The speed of escalator can be calculated as,

$v_{escalator}=\frac{x}{t}=\frac{18.3}{47.8}=0.383\ m/s$

Relative velocity

$v_{relative}=v_{escalator}+v_{person}\\\\v_{relative}=0.383+0.521=0.904\ m/s\\$

Therefore total time required to take the person to get to the top

$t=\frac{x}{v_{relative}}= \frac{18.3}{0.904}=20.243\ s$

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A 0.500-kg stone is moving in a vertical circular path attached to a string that is 75.0 cm long. The stone is moving around the

Semenov [28]

Answer:

B. 7.07 m/s

Explanation:

The velocity of the stone when it leaves the circular path is its tangential velocity, $v$ , which is given by

$v=\omega r$

where $\omega$ is the angular speed and $r$ is the radius of the circular path.

$\omega$ is given by

$\omega = 2\pi f$

where $f$ is the frequency of revolution.

Thus

$v=2\pi fr$

Using values from the question,

$v=2\pi\times 1.50\times0.75$

<em>Note the conversion of 75 cm to 0.75 m</em>

$v=2\times3.14\times 1.50\times0.75 = 9.42\times0.75 = 7.065=7.07$

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3 years ago

Jumping up is work against gravity why

lions [1.4K]

Answer:

gravitational force attract us towards the ground

Explanation:

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3 years ago

A solenoidal coil with 26 turns of wire is wound tightly around another coil with 350 turns. The inner solenoid is 20.0 cm long

noname [10]

Answer:

Part a)

$\phi = 2.76 \times 10^{-7} T m^2$

Part B)

$M = 5.52 \times 10^{-5} H$

Part C)

$EMF = 0.1 V/s$

Explanation:

Part a)

Magnetic field due to a long ideal solenoid is given by

$B = \mu_0 n i$

n = number of turns per unit length

$n = \frac{N}{L}$

$n = \frac{350}{0.20}$

$n = 1750 turn/m$

now we know that magnetic field due to solenoid is

$B = (4\pi \times 10^{-7})(1750)(0.100)$

$B = 2.2 \times 10^{-4} T$

Now magnetic flux due to this magnetic field is given by

$\phi = B.A$

$\phi = (2.2 \times 10^{-4})(\pi r^2)$

$\phi = (2.2 \times 10^{-4})(\pi(0.02)^2)$

$\phi = 2.76 \times 10^{-7} T m^2$

Part B)

Now for mutual inductance we know that

$\phi_{total} = M i$

$\phi_{total} = N\phi$

$\phi_{total} = 20(2.76 \times 10^{-4})$

$\phi_{total} = 5.52 \times 10^{-6}$

now we have

$M = \frac{5.52 \times 10^{-6}}{0.100}$

$M = 5.52 \times 10^{-5} H$

Part C)

As we know that induced EMF is given as

$EMF = M \frac{di}{dt}$

$EMF = 5.52 \times 10^{-5} (1800)$

$EMF = 0.1 V/s$

3 0

3 years ago

The speed of a car during a trip is represented in the graph. Compare distance and displacement at four hours into the trip.

mezya [45]

Answer:

The answer to your question is: D.

Explanation:

Distance refers to the amount of space between two points, it is a scalar quantity.

Displacement refers to the space between two points, measure from the minimum path linking them, it is a vector quantity.

I'm not agree with these answers, because the total distance is approximately 500km.

A) The distance traveled is 300 km. This answer is not correct.

B) Distance is 300 km and displacement is 0 km. This answer is not correct because the displacement is also 500 km.

C) Distance is 300 km/hour and displacement is 300 km. 300 km/h is a measure of speed not of distance, this option is wrong.

D) Both distance traveled and displacement are 300 km. I think this is the correct answer because distance and displacement measure the same. but I think both measure 500 km.

7 0

3 years ago

Read 2 more answers

A 1.60 m cylindrical rod of diameter 0.550 cm is connected to a power supply that maintains a constant potential difference of 1

bija089 [108]

1.

Answer:

Part a)

$\rho = 1.35 \times 10^{-5}$

Part b)

$\alpha = 1.12 \times 10^{-3}$

Explanation:

Part a)

Length of the rod is 1.60 m

diameter = 0.550 cm

now if the current in the ammeter is given as

$i = 18.7 A$

V = 17.0 volts

now we will have

$V = I R$

$17.0 = 18.7 R$

R = 0.91 ohm

now we know that

$R = \rho \frac{L}{A}$

$0.91 = \rho \frac{1.60}{\pi(0.275\times 10^{-2})^2}$

$\rho = 1.35 \times 10^{-5}$

Part b)

Now at higher temperature we have

$V = I R$

$17.0 = 17.3 R$

R = 0.98 ohm

now we know that

$R = \rho \frac{L}{A}$

$0.98 = \rho' \frac{1.60}{\pi(0.275\times 10^{-2})^2}$

$\rho' = 1.46 \times 10^{-5}$

so we will have

$\rho' = \rho(1 + \alpha \Delta T)$

$1.46 \times 10^{-5} = 1.35 \times 10^{-5}(1 + \alpha (92 - 20))$

$\alpha = 1.12 \times 10^{-3}$

2.

Answer:

Part a)

$i = 1.55 A$

Part b)

$v_d = 1.4 \times 10^{-4} m/s$

Explanation:

Part a)

As we know that current density is defined as

$j = \frac{i}{A}$

now we have

$i = jA$

Now we have

$j = 1.90 \times 10^6 A/m^2$

$A = \pi(\frac{1.02 \times 10^{-3}}{2})^2$

so we will have

$i = 1.55 A$

Part b)

now we have

$j = nev_d$

so we have

$n = 8.5 \times 10^{28}$

$e = 1.6 \times 10^{-19} C$

so we have

$1.90 \times 10^6 = (8.5 \times 10^{28})(1.6 \times 10^{-19})v_d$

$v_d = 1.4 \times 10^{-4} m/s$

8 0

3 years ago