Physics - April 2007

...varies with time t according to Flux = 3at^3 - bt^2, with a = 1.5s^-3 m^2T, and b = 6.1 s^-2m^2T. The resistance of the ring is 2.7 ohms. Determine the maximum current induced in the ring during the interval from t1 = -3.6 s to t2 = 1.6 s.

I began this problem by doing the derivative of the equation given for flux. The new derived equation I obtained was t(13.5t - 12.2). I know that Emf = dFlux/dt. I just don't know what the t in my derived flux equation represents, t1 or t2, or if I have to use both and subtract. In any case, I know to find current you just divide the induced emf by the resistance. Any help would be appreciated.

2007-04-10 06:07:49 · 2 answers · asked by mmrage318 1

Tarzan swings on a 25.0 m long vine initially inclined at an angle of 34.0° with the vertical.
(a) What is his speed at the bottom of the swing if he starts from rest?
m/s
(b) What is his speed at the bottom of the swing if he pushes off with a speed of 3.00 m/s?
m/s

2007-04-10 05:41:33 · 3 answers · asked by Anonymous

Temperature conversion.

2007-04-10 05:38:58 · 3 answers · asked by Vikas Kumar 1

2007-04-10 05:16:21 · 1 answers · asked by Anonymous

this is just for my physics project....

2007-04-10 04:50:27 · 8 answers · asked by Dora the Exploiter 4

2007-04-10 04:32:04 · 6 answers · asked by Anonymous

2007-04-10 04:20:09 · 1 answers · asked by Anonymous

2007-04-10 02:41:43 · 13 answers · asked by supercalofragilistic 3

because the earth is spinning would this helicopter be in a different place after 12 hours?

2007-04-10 02:21:38 · 18 answers · asked by h_moinian1981 1

I want to make a van der graaf generator. So I want to find a smooth metal sphere between 10 and 30mm in diameter. I fact it does'nt even need to be spherical. Egg shape or even a donut / torus would do, as long as it is roundish and has no points. I am in the UK, so it needs to be available here. It also needs to be cheap. Any ideas of where to look or things to adapt would be very welcome.

2007-04-10 02:20:53 · 1 answers · asked by mot 1

why is this above line written on car rear view mirrors as we all know that the convex mirror used there forms the image closer than it really is(ie v is always less than u in convex mirror).

i know that the image is smaller so they should write "larger" than "closer". Why closer??????

2007-04-10 00:49:29 · 5 answers · asked by Annie 2

A physics student with too much free time drops a watermelon from the roof of a building. He hears the sound of the watermelon going "splat" after a time interval of Delta(t)

You may ignore air resistance. How high is the building? The speed of sound is v_s.

2007-04-09 23:34:37 · 1 answers · asked by Anonymous

Do they allow electrons to flow freely through them or do the electrons stay on them?

I had a question that asked what would happen to a pith ball that was touching an insulated metal rod, and at the other end of the insulated rod there was a positively-charged rod touching it as well.
If you could tell me what happens to the pith ball in the above question as well, thanks!

2007-04-09 23:24:53 · 1 answers · asked by dottiesunfish 3

A circular region of radius R = 3.00 cm in which a uniform electric flux is directed out (imagine it on your screen, it's pointing OUT). The total electric flux enclosed by the region is given by Phi ^ elec = (3.00 mV m/s)t, where t is time.

What is the magnitude of the magnetic field that is induced at radial distances (a) 2.00 cm and (b) 5.00 cm?

Explain your work, and good luck! :)

2007-04-09 19:21:42 · 2 answers · asked by Anonymous

What net force acts on a positive charge of 4mC at a point where the electric field strength is 400 N/C?

.......
Whats mC?
What equation do I use? E=kq/r^2?

2007-04-09 19:12:30 · 3 answers · asked by Keshawn 1

is the electric field between two like sign electric charges always stronger than it would be if one of the two charges is removed? why or why not?

2007-04-09 17:11:23 · 1 answers · asked by stumped on physics 2

I am wondering if a magnetic field will effect light?
If it does, can you suggest an experiment I can do at home to illustrate this.
Thank you in advance.

2007-04-09 17:06:02 · 3 answers · asked by Anonymous

Hi, I'd like to learn how to do this problem, I solved it once, but I came up with the wrong answer.
Here is a diagram of the circuit; http://i11.tinypic.com/2hsao0n.jpg

We are to find the potential difference (delta V) between point A and B, and the current through the 20 ohm resistor on the right.

I'm having trouble understanding the Kirchoff Law stuff and what not too. :S
Best answer goes to whoever can help me with both ^^;

2007-04-09 16:52:35 · 3 answers · asked by ☆ 2

2007-04-09 16:29:14 · 3 answers · asked by Rich 2

2007-04-09 15:48:20 · 1 answers · asked by Anonymous

Im confused what pC stands for and um

Question: What is the electric field strength 5.0um from a charge of 22pC?


Formula should be= kq/r² N/C

So what do I do next

2007-04-09 15:37:16 · 5 answers · asked by Kodos 1

What design would make the most efficient electromagnet. Must lift most paperclips. Then the number of paperclips will be divided by the current to get the efficiency. It cannot exceed 125 cm cubed in volume. It will be hooked up to a 5 volt power source. The wire hook in leads need to be at least 30 cm long. I cant use wire more than 1 mm in diameter. The resistance can't be under 0.5 ohms.

2007-04-09 15:26:20 · 2 answers · asked by yaya 2

Hot water at 90°C is poured into a large Styrofoam cup that contains water at 20°C. The final temperature of the mixture is 75°C, closer to the initial temperature of the hot water.

a.) Which mass of water was the greatest, the hot or the cold water? Does that mean that the heat lost by the water is less than the heat gained by cold water? Explain.

b.) Calculate the ratio of cold water to hot that would give this result. Start with energy conservation: Qн + Qс = 0.

c.) If there was 150g of hot water calculate how much heat was exchanged?

2007-04-09 14:54:24 · 3 answers · asked by Lakers 1

A transformer has 20 turns of wire in its primary coil and 40 turns on its secondary coil.

(a) Is this a step-up or step-down transformer?
step down
step up

(b) If an alternating voltage with an effective voltage of 120 V is applied to the primary, what is the effective voltage induced in the secondary?
______V

2007-04-09 14:43:56 · 2 answers · asked by bibun 2

Two well known and indisputable facts are 1) the fist of Chuck Norris can break through any object, and 2) the jaw of Chuck Norris is unbreakable. So what happens when an unstoppable force collides with an impervious barrier?

2007-04-09 14:35:52 · 6 answers · asked by Anonymous

Snow is falling vertically at a constant speed of 8.0 m/s. At what angle from the vertical do the snowflakes appear to be falling as viewed by the driver of a car traveling on a straight, level road with a speed of 50 km/h?

2007-04-09 14:17:01 · 2 answers · asked by H.A. 2

I'm sure that with the way I cook, I do have something radioactive in there too...

2007-04-09 14:10:58 · 8 answers · asked by aanstalokaniskiodov_nikolai 5

A rotating fan completes 1200 revolutions every minute. Consider the tip of a blade, at a radius of 0.15 m. a)through what distance does the tip move in one revolution? What are b) the tip's speed and c) the magnitude of its acceleration? d) What is the period of the motion?

2007-04-09 13:57:15 · 2 answers · asked by Danyal Ali 1

Is it possible for a body to exist somewhere in the universe that has no forces whatsoever acting on it? Explain why please.

Thanks!

2007-04-09 13:24:56 · 4 answers · asked by aeckzs 1

2007-04-09 12:41:54 · 5 answers · asked by Birk80808 1