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3 years ago

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A 10.0-cm-long wire is pulled along a U-shaped conducting rail in a perpendicular magnetic field. The total resistance of the wi

re and rail is 0.350ohms . Pulling the wire at a steady speed of 4.0m/s causes 4.20W of power to be dissipated in the circuit. part A: How big is the pulling force? part B: What is the strength of the magnetic field?

1 answer:

Veronika [31]3 years ago

5 0

A) 1.05 N

The power dissipated in the circuit can be written as the product between the pulling force and the speed of the wire:

$P=Fv$

where

P = 4.20 W is the power

F is the magnitude of the pulling force

v = 4.0 m/s is the speed of the wire

Solving the equation for F, we find

$F=\frac{P}{v}=\frac{4.20 W}{4.0 m/s}=1.05 N$

B) 3.03 T

The electromotive force induced in the circuit is:

$\epsilon=BvL$ (1)

where

B is the strength of the magnetic field

v = 4.0 m/s is the speed of the wire

L = 10.0 cm = 0.10 m is the length of the wire

We also know that the power dissipated is

$P=\frac{\epsilon^2}{R}$ (2)

where

$R=0.350 \Omega$ is the resistance of the wire

Subsituting (1) into (2), we get

$P=\frac{B^2 v^2 L^2}{R}$

And solving it for B, we find the strength of the magnetic field:

$B=\frac{\sqrt{PR}}{vL}=\frac{\sqrt{(4.20 W)(0.350 \Omega)}}{(4.0 m/s)(0.10 m)}=3.03 T$

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Answer:

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Mathematically,

$\frac{P_1}{T_1}=\frac{P_2}{T_2}$

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$P_2\text{ and }T_2$ are the final pressure and temperature of the gas.

We are given:

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Putting values in above equation, we get:

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3 years ago

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Answer:

If the system consists of the block only, the work done by the gravity is negative.

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Explanation:

If the system consists of the block only, then the system experiences two external forces: one exerted by the hand that lifts the block vertically upward and other exerted by the earth (gravity), which is opposed to the movement of the system, so the work done by gravity is negative.

On the other hand, if the system consists of the block and the earth, then only exists a external force which is the exerted by the hand. So, the force exerted by gravity is zero.

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4 years ago

As a woman walks, her entire weight is momentarily placed on one heel of her high-heeled shoes. Calculate the pressure exerted o

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Answer:

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The pressure exerted on the floor is 3335400 N/m² or 483.75889 lb/in²

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So we have $v_{AT}=(95km/h)-(75Km/h)=20Km/h$ .

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3 years ago