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3 years ago

You could increase the mechanical efficiency of this screw by

1 answer:

3 0

I can't see the screw (if you'll pardon the expression), so I don't know a thing about it, and can't answer the question. There's no given information in the question.

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The current through a certain heater wire is found to be fairly independent of its temperature. If the current through the heate

bearhunter [10]

Answer:

Explanation:

the formular for the relationship between energy and current is E= I²Rt (Heat energy)

the heater is fairly independent of its temperature , and given the time to be constant.

with the current being doubled,

E = I² Rt

E/ I² = K

$\frac{E1}{I1^{2} }$ = $\frac{E2}{I2^{2} }$

E2 = $\frac{E1* I1^{2} }{I1^{2} }$

I2 = 2* I1

E2 = E1 * 4*I1² / I1²

dividing , we have that E2 = 4 * E1

which means during the same time interval the amount of energy will increase by a factor of four.

7 0

4 years ago

A student is experimenting with some insulated copper wire and a power supply. She winds a single layer of the wire on a tube wi

OverLord2011 [107]

Answer:

$P=214.7187\,W$

Explanation:

Given that:

Diameter of the solenoid, $D=10\,cm=0.1\,m$

length of the solenoid, $L=90\,cm=0.9\,m$

diameter of the wire, $d=0.1\,cm=10^{-3}\,m$

magnetic field at the center of the solenoid, $B=7.4\times 10^{-3}\,T$

Now we need the no. of turns incorporated in the length of 90 cm:

$N=\frac{Length\,\,of\,\,solenoid}{diameter\,\,of\,\, wire}$

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

$N=\frac{0.9}{10^{-3}}$

$N=900\,\,turns$

For solenoids we have:

$B=\mu.n.I$ ...............................(1)

where:

$\mu=$ permeability of the medium

n = no. of turns per unit length

I = current in the coil

So,

$n=\frac{900}{0.9}$

$n=1000\,turns\,.\,m^{-1}$

Now putting the respective values in the eq. (1)

$7.4\times 10^{-3}=4\pi\times10^{-7}\times 1000\times I$

$I=5.8887\,A$

For copper we have resistivity:

$\rho=1.72\times 10^{-8}\, \Omega.m$

We know that resistance is given by:

$R=\rho.\frac{l}{a}$ .....................................(2)

where:

l = length of the conducting wire

a = cross sectional area of the conducting wire

Now we need the length (l) of the wire:

Circumference of the solenoid,

$C=\pi.D$

$C=0.1\pi\,m$

$\therefore l=C\times N$

$l=90\pi\,m$

Cross-sectional area of wire:

$a=\pi.\frac{d^2}{4}$

$a=\pi. \frac{(10^{-3})^2}{4}\,m^2$

Resistance from eq. (2):

$R=1.72\times 10^{-8}\times \frac{90\pi}{\pi. \frac{(10^{-3})^2}{4}}$

$R=6.192 \,\Omega$

For power we have:

$P=I^2.R$

$P=5.8887^2 \times 6.192$

$P=214.7187\,W$

6 0

3 years ago

A magnetic field is perpendicular to the plane of a single-turn circular coil. The magnitude of the field is changing, so that a

scoundrel [369]

To solve this problem we will apply the concepts related to magnetic flux and induced voltage. This last expression understood as the variation of the magnetic flux over time and, in turn, the magnetic flux expressed as the variation of the magnetic field in a certain area.

Magnetic flux through the circular coil is given as

$\Phi_C = B(\pi r^2)$

The induced voltage is the change of the magnetic flux across the time, then

$\epsilon_{emf,C} = \frac{B(\pi r^2)}{t}$

At the same time the magnetic flux through the square coil would be given as,

$\Phi_S = B(r^2)$

And the induced voltage EMF will be

$\epsilon_{emf,s} = \frac{B(r^2)}{t}$

Equating both expression we have

$\epsilon_{emf,s} = \frac{\epsilon_{emf,C}tr^2}{\pi r^2t}$

$\epsilon_{emf,s} = \frac{0.74V}{\pi}$

$\epsilon_{emf,s} = 0.23355V$

Therefore the emf induced in the square coil is 0.23355V

7 0

3 years ago

List two examples of the following states of matter: solids, liquids, and gases. Please answer in NO LESS THAN 3 complete senten

slavikrds [6]

Answer:

Matter can exist in one of three main states: solid, liquid, or gas. Solid matter is composed of tightly packed particles. A solid will retain its shape; the particles are not free to move around. Liquid matter is made of more loosely packed particles.

Key Takeaways: Examples of Solids, Liquids, and Gases

A solid has a defined shape and volume. A common example is ice. A liquid has a defined volume, but can change state. An example is liquid water.There are four natural states of matter: Solids, liquids, gases and plasma. The fifth state is the man-made Bose-Einstein condensates. In a solid, particles are packed tightly together so they don't move much.

Explanation:

7 0

3 years ago

Automobile engines AND steam engines are examples of ______. a. internal combustion engines b. heat engines c. external combusti

uranmaximum [27]

Answer: B. Heat engines

Explanation:

8 0

3 years ago

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