Physics - February 2007

2007-02-23 13:41:09 · 5 answers · asked by Anonymous

When you insert a dielectric between the plates of a capacitor, the energy of the capacitor decreases.

1). Where does the energy go to to create the difference from before?

2). Also, what would happen to the energy if the capacitor remained connected to the battery and the dielectric was inserted?

2007-02-23 13:32:46 · 4 answers · asked by Justcurious 2

The speed of sound in water is 1498 m/s. A sonar signal is sent straight down from a ship at a point just below the surface of the water surface, and 1.80 seconds later, the reflected signal is detected. How deep is the water?

Please help me with this problem.
I don't understand it.

2007-02-23 13:31:22 · 4 answers · asked by swimmertommy 1

i dont know what my deal is. i get shocked almost every time i touch something. My bedpost, the shower nozzle, a shopping cart...sometimes i go to kiss my boyfriend and ill zap his nose with mine and it hurts like hell! and if its dark you can see the spark! i am definitely not made of metal. so how can i stop conducting so much electricity?

2007-02-23 13:30:49 · 7 answers · asked by Megabeth 3

Water waves in a shallow dish are 6.0 centimeters long. At one point, the water moves up and down at a rate of 4.8 oscillations per second.

a. What is the speed of the water waves?
b. What is the period of the water waves?

2007-02-23 13:27:23 · 2 answers · asked by swimmertommy 1

An ocean wave has a length of 12.0 meters. A wave passes a fixed location every 3.0 seconds. What is the speed of the wave?

This problem seems easy.
But I'm confused. Please help.

2007-02-23 13:21:47 · 1 answers · asked by swimmertommy 1

2007-02-23 13:05:45 · 8 answers · asked by hikarudoll 1

I need help for solving specific heat for my upcoming exam. How can i compute the specific heat? Is there an easy technique? if there is, please tell me how?
Sample problem:
A thermos bottle contains 80g of water at 15 degree celcius. Into this placed 40g of metal at 85 degree celcius after equilibrium is established, the temparature of the water and metal is 35 degree celcius. What is the specific heat of metal? Assume no heat loss to the thermos bottle?
(if there is an answer of (3400gdegree celcius - (subtract) 1400g degree celcius) where do 1400g degree celcius comes from?

2007-02-23 13:03:11 · 2 answers · asked by Jeniv the Brit 7

this formula was formulated by Einstien.

2007-02-23 12:38:52 · 2 answers · asked by Dexter P 1

At the grocery store you pick up a can of beef broth and a can of chunky beef stew. The cans are identical in diameter and weight. Rolling both of them down the aisle with the same initial speed, you notice that the can of chunky stew rolls much farther than the can of broth. Why?

2007-02-23 12:33:27 · 3 answers · asked by Anonymous

2007-02-23 12:27:58 · 9 answers · asked by muttenheimer 1

2007-02-23 12:13:56 · 4 answers · asked by Jason432 2

At the grocery store you pick up a can of beef broth and a can of chunky beef stew. The cans are identical in diameter and weight. Rolling both of them down the aisle with the same initial speed, you notice that the can of chunky stew rolls much farther than the can of broth. Why?

2007-02-23 12:12:47 · 3 answers · asked by bedfordmarine2003 2

2007-02-23 12:02:42 · 1 answers · asked by go 1

I need help with part b, I know part a.

An athlete executing a long jump leaves the ground at a 35 degree angle & travels 6.8m.
a) what was the takeoff speed? 8.3.
b)If this speed were increased by just 2%, how much longer would the jump be?.

So far this is what I did but I got the wrong answer....
8.3 x .02 = .166 --> V0=8.3 + .166=8.466..
Vx0=8.466cos(35)=6.93
Vy0=8.466sin(35)=4.85

y=y0 + Vy0t + .5(-9.8)(t^2)


help am i doing it right?

2007-02-23 12:01:41 · 2 answers · asked by Anonymous

2007-02-23 11:59:33 · 4 answers · asked by Jesse P 1

Suppose that the force due to water resistance of a microbe swimming through a fluid is F=bv, where v is the constant swimming speed and b is a constant. Assuming that the microbe is expending a power P in swimming, the maximum speed of the object is...



1. sqrt(P/b)

2. P/b

3. P/sqrt(b)

2007-02-23 11:56:43 · 4 answers · asked by Anonymous

Assuming that muscles have an efficiency of 22 percent for converting energy into work, how much energy (in kJ) is expended by an 80-kg person in climbing stairs through a vertical distance of 25 m.

2007-02-23 11:55:43 · 2 answers · asked by Anonymous

A record was set for stair climbing when a man ran up the 1600 steps of the Empire State Building in 10 minutes and 59 seconds. If each step has a height of 0.20 m, and the man's mass was 75 kg, what was his average power output (in Watts) during the climb?

2007-02-23 11:54:58 · 4 answers · asked by Anonymous

A series RCL circuit has a resonant frequency of 1530 Hz. When operating at a frequency other than 1530 Hz, the circuit has a capacitive reactance of 5.0 and an inductive reactance of 30.0 .

What is the value of the inductance (L)?

What is the value of C, the capacitance?

2007-02-23 10:50:35 · 2 answers · asked by christian m 2

am i right in assuming that
1.) light, heat, radio waves, and power are all the same kind of thing. and converting electricity to heat, x-rays, or light is simply changing the frequency of the same thing.
2.) wavelengths of gamma are the result of the decay of certain radioactive elements
3.) heat, x-rays, Am radio, ect.. are all photons?
Also do photons have mass?
And i heard that light has been succesfully stopped, yet when it returned to a vaccum it's speed immediately went to 3*10^8 meters per second is this true?

2007-02-23 10:44:07 · 5 answers · asked by philip32189 2

A section of an advertising sign consists of a long tube filled with neon gas having electrodes inside at both ends. A uniform electric field of 20 kN/C is set up between the electrodes, and neon ions accelerate along the length of the tube. Given that the ions each have a mass of 3.35 X 10^-26 kg and are singly ionized, determine their acceleration.

2007-02-23 10:39:58 · 2 answers · asked by hpage 3

A small positively charged object is placed, at rest, in a uniform electric field in vacuum. Write an equation giving its speed after a time t in terms of its mass m and charge q.

2007-02-23 10:33:28 · 1 answers · asked by hpage 3

The following thought experiment is driving me mad, but I can't seem to reconcile relativity with the Bernoulli eqn.

In a classic textbook example you are asked to imagine that you are a smoker sitting on a fast moving train travelling through a narrow tunnel with the window open. The fast flowing air outside of the carriage means a reduced pressure, and so the air (and thus the smoke) from within the carriage is pushed out through the window.

However, now imagine you are a smoker sitting in the tunnel by the track watching the train go past. You see the air in the carriage moving faster, and so the air inside the carriage is at a lower pressue. Your smoke is pushed into the carriage.

Now these can't both be true.

We can even forget the specifics of the train example, and say that this must be true of any fluid flow with differential speed. It seems that Benoulli requires an absolute velocity, but relativity says we can't have one. I must be missing something fundamental, but what?

2007-02-23 10:17:33 · 9 answers · asked by Andy G 1

A pitcher throws a .142kg baseball at 47.2 m/s. As it travels a distance of 19.4m, the ball slows to 42.5 m/s because of air resistance. Find the change in temperature of the air through which the ball passes. The following assumptions may be made: molar specific heat of air is (7R/2), molar mass of air is 28.9 g/mole, and the cover insulates the interior of the ball so the ball's temperature does not change. The temperature change happens in a cylinder of 19.4m length and radius of 3.7cm. Air temperature is 20 degrees Celcius.

2007-02-23 10:06:05 · 2 answers · asked by Shane W 1

Specificaly in the formula for determing Rotational Energy : 1/2Iw^2,
Where I = Moment of inertia and w = Angular Velocity.

Wikipedia says that angular velocity is used to determine Angular Speed/Frequency, but the formulas are VASTLY different for each, so would they even result in the same unit of measure let alone, the same values?

The Angular Velocity formulas look like chinese to me and seem to0 complicated for the application of just determining energy of rotation. Angular Speed formula looks more like it, but thats not what the Rotational Energy formula calls for, is Wikipedia wrong or are they interchangable?

2007-02-23 09:55:37 · 3 answers · asked by Ray of Freaking Sunshine! 2

2007-02-23 09:50:37 · 1 answers · asked by Anonymous

The speed of light is 3.0*10^8m/s. The speed of sound is 344m/s. A flash of lightning occurs in a storm 1.0*10^4m away. How many seconds does it take for us to see the lightning and hear the thunder?

2007-02-23 09:13:53 · 4 answers · asked by Anonymous

2007-02-23 09:13:45 · 3 answers · asked by cooper243 2

For what distance from ground zero would the radtiation be a factor also?

2007-02-23 09:06:45 · 3 answers · asked by artinreno 1