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Comment on please help physics question? by gp4rts

gp4rts — Fri, 10 Sep 2010 08:42:58 +0000

V = -dΦ/dt, where Φ is the total flux in webers. 1 tesla = 1 wb/m². For constant field of 0.10 T,

V = -0.10*dA/dt

where A is the normal component of the coil area in the direction of the field

A =π*r²*cps(ω*t)

dA/dT = -ω*π*r²*sin(ω*t)

the peak value of dA/dt is -ω*π*r² (where sin = 1)

Vp = 0.10*ω*π*r² per turn of the coil

The number of turns is 5.1/(2*π*r), so total voltage is

Vt = 5.1/(2*π*r)*0.10*ω*π*r² = 0.255*ω*r

Vt = 2.14 v

Comment on Physics Homework Help Anyone? by TooKewl

TooKewl — Thu, 09 Sep 2010 08:45:26 +0000

Hey!

I can’t answer all of the questions, but I think I know the answers to two of them.

The answer to question 2 is b.

and

The answer to question 8 is a.

I hope I helped.

Comment on Physics Homework Help Anyone? by John R

John R — Thu, 09 Sep 2010 08:45:26 +0000

You may check physics homework help website below.

Comment on Generators And Motor Questions, know them? by goober

goober — Wed, 08 Sep 2010 11:07:05 +0000

1. C, the heaviest wire.
2. AC
3. DC
4. The closest one is watts, but that is power or work per unit time. Work is measured in Joules.
5. Watts
6. Currents generate magnetic fields that spin the motor.
7. magnetic fields generate electrical fields in moving conductors that make electrons move
8.direct current
9. alternating current
10. it converts mechanical energy into electrical energy

Comment on homework help? (5 multiple choice) =]? by vkvanil

vkvanil — Tue, 07 Sep 2010 13:31:28 +0000

1 (D); 2(B); 3(C); 4(B); 5(D)

Comment on Generators use a magnetic field of which of the following to produce an electric current? by Nana

Nana — Mon, 06 Sep 2010 11:07:32 +0000

electromagnetic induction

Comment on Generators use a magnetic field of which of the following to produce an electric current? by Brian G

Brian G — Mon, 06 Sep 2010 11:07:32 +0000

I disagree. I would go with "all of the above."

Comment on Generators use a magnetic field of which of the following to produce an electric current? by P A

P A — Mon, 06 Sep 2010 11:07:32 +0000

its definitely option C

Comment on I need help with 2 basic quetions? by science teacher

science teacher — Sun, 05 Sep 2010 11:07:15 +0000

A motor works by running current through a coil that creates an electromagnet that attracts an arm. A DC motor uses a make and break circuit to keep the arm rotating. An AC motor uses a commutator to change the direction of the attraction, as the direction of the power changes, so that the arm keeps rotating. This rotational motion is used to cause something to rotate such as a saw blade, or through gears change the direction of the motion.

A generator uses outside motion such as steam, water power, moving water, wind, to move a coil past a magnet. This movement causes a current to run in the coil , this is electricity.

Comment on what is the max emf output? what would be the max emf output if 10 such loops were used instead? by Steve

Steve — Sat, 04 Sep 2010 08:43:56 +0000

The formula is
emf = NBAω = NBA(2πf) = 1*.015*(.1*.1)(2π*60)
emf = .0565 V

Clearly, 10 loops would produce 10 times the emf……