Physics - July 2007

Topic in physics

2007-07-06 02:51:24 · 2 answers · asked by Jim J 1

1. In a photoelectric-effect experiment, light of wavelength 420 nm is incident on a sample of sodium. The work function of sodium is 3.67 x 10^-19 J.Calculate the stopping potential required to just stop all electrons from reaching the anode.

2. Light of a different wavelength is incident on a sample of calcium (work function 4.65 x 10^-19 J) The same stopping potential as in (1) is required to just stop all electrons from reaching the anode. Is the wavelength in this case bigger or smaller than in (1) Justify your answer.

2007-07-06 02:41:18 · 2 answers · asked by walt 2

1.) What is the wavelength of a 440 Hz sound wave in the air?

2.) While riding in your boat, you notice one wave pass by every two seconds. If the actual frequency of the waves is 1 Hz, with what speed are you moving through the water? The speed of the waves is 5 m/s. Are you moving towards the waves or away?

2007-07-06 02:41:18 · 1 answers · asked by Jenny V. 2

2007-07-06 01:37:49 · 6 answers · asked by Grinning Football plinny younger 7

2007-07-06 01:22:55 · 57 answers · asked by manish u 2

There is a cylinder which is 12 cm long placed in a beaker filled with water, the rim of the cylinder is 1cm above water level. The cylinder has some sand in it to stabilize it. Then, oil is added into THE CYLINDER (which contains the sand) and the specific density of oil is 0.8. The question is when the oil is added to the sand, will the cylinder float or sink????

2007-07-05 20:33:58 · 5 answers · asked by Wonder 1

2007-07-05 20:09:23 · 1 answers · asked by Amin Z 1

We all know that our vision is based on reflection and refraction of light from objects which is received by our eyes and translated back to objects by our brain. So, when you are traveling at speed of light, can you see at all? If yes, how? If no, why not?

Think about it before you answer.

2007-07-05 19:41:47 · 4 answers · asked by Anonymous

We now have things like third dimension, stuff like that. What is a dimension and how many dimensions are out there and what are their uses?

2007-07-05 19:39:59 · 12 answers · asked by DSims 1

My friends and I are doing our final year project on this distillation of rainwater to pure drinking water. Then we need to for out the actual angle for reflecting the sunlight to a specific point of our tube.

2007-07-05 19:12:07 · 3 answers · asked by wreany 1

we all knows that atoms consist of the nucleus with the electrons orbiting it and between these particles there is empty space. now say we got 2 things each has their atoms lined up perfectly with their corresponding empty spaces relate to each others particles so if we then time it perfectly could we pass these 2 objects through each other?

2007-07-05 18:26:43 · 9 answers · asked by Harold s 2

can u suggest a site where i can get get a good description of fourier transform of fullwave rectifier outputs and square wave?

2007-07-05 18:17:44 · 1 answers · asked by welma 2

A child exerts a force of 2.0N [forward] on a stationary 4.0kg tricycle for 1.2 seconds. Calculate the acceleration of the tricycle.

So... All i could think of is given : force of 2.0N, Time of 1.2s and a mass of 4.0kg.
Required: Acceleration
Analysis: Im not sure which formula to use? I cant use a = velocty/time because I do not know velocity... and i cant use V=a x time because i dont know veloctiy. Im confused? Please help? Thanks!

2007-07-05 17:06:12 · 2 answers · asked by Daniel C 2

If we make a hole in ground and jump in it means you will reach its bottom surface because of gravity... WHAT WILL HAPPEN IF YOU JUMP IN THE HOLE MADE IN EARTH WHICH REACHES NEXT END... LIKE DRILLED FORM INDIA WILL REACHES US... COULD YOU REACH US??????

2007-07-05 16:53:26 · 16 answers · asked by Anonymous

Q.1 A ball is thrown vertically upward from the ground with a speed of 25 m/s. On its way down it is caught at a point 5m above the ground. How long did the trip take?

Q.5 The time period of a pendulum is 2 seconds at the surface of the earth calculate its time period on the surface of the moon where the value of acceleration due to gravity is one-sixth that of the value of ‘g’ at the surface of the earth.

Q.7 If a diffraction grating produces a first order spectrum of light of wavelength 6*10^-7 m at an angle of 20 from the normal: calculate the number of lines per mm.

2007-07-05 16:53:20 · 1 answers · asked by Anonymous

This may not be answerable. I'm not sure. Or maybe not in the form I am asking. Could you sustain 1 earth gravity of acceleration in an automobile?

2007-07-05 16:40:56 · 5 answers · asked by darev2005 1

if something accelerates at an angle, say 3m/s^2 at 30 degrees above horizon, does that mean it accelerate cos(30)3 horizonally and sin(30)3 vertically?

2007-07-05 16:11:26 · 3 answers · asked by Ha!! 2

A rocket is launched from rest and moves in a straight line at 70 deg above the horizontal with an acceleration of 46 m/s^2. After 30s of powered flight, the engines shut off and the rocket followsa parabolic path back to earth.(a) Find the time of flight from launching to impact on earth.(b) What is the maximum altitude reached? (c) What is the distance from launch pad to impact point?

2007-07-05 15:28:51 · 2 answers · asked by Anonymous

Ball A is dropped from the top of a building at the same instant that ball B is thrown vertically upward from the ground. When the balls collide, they are moving in opposite directions, and the speed of A is twice the speed of B. At what fraction of the height of the building does the collision occur.

2007-07-05 15:17:54 · 6 answers · asked by Anonymous

We're going through a heatwave and my house goes up to 80 degrees in the daytime. I have almost unlimited cheap access to cool ground water (64 degrees). Is it practically feasible to fill my bathtub and use it as a heat sink? How would I do this?

2007-07-05 14:47:01 · 4 answers · asked by Anonymous

What do you do if the traffic light flashes red and green (alternating). O_o i got that as a question

2007-07-05 14:18:46 · 4 answers · asked by Rawrie. 2

very very long shot .. like the one in a movie called Shooter.
in the movie he said it may have a little effect ..

i wanna know if that is true ..

2007-07-05 14:17:47 · 8 answers · asked by Anonymous

i read a newspaper today. its talks about a falling feather hits the ground in the same time as a falling rock in vacuum. i thought about that for quite some times. i don't really get it. a feather falls slower than a rock cuz of air resistance. if a rock falls faster even with air resistance, it should fall even faster without air resistance. so is that mean the speed of gravity constant?

2007-07-05 12:01:55 · 12 answers · asked by ۞_ʞɾ_۝ 6

Magnets have a magnetic field. If two large magnets are put in a car, and their magnetic fields repel, couldnt that energy be used some how to propel car? Obviously magnetic fields either attract or pull (push away). I would think that if the magnets were big enough, you could somehow use that energy and propel a car and it would have zero emmisions. Or I guess you could use a small motor to push the magnets back and forth to creat this energy. Does this make sense??

2007-07-05 12:01:32 · 10 answers · asked by Andy Green 2

2007-07-05 09:39:19 · 10 answers · asked by Anonymous

2007-07-05 09:31:15 · 33 answers · asked by Anonymous

please include the energy changes from the burning of energy at the elecrical plant and sound energy

2007-07-05 09:21:23 · 4 answers · asked by *super* *star* 1

Yes. Please embellish!

I really would like your opinon about this. Please answer with info to back up your position.

Balderdash is the game!

Best answer wins!

2007-07-05 09:08:12 · 2 answers · asked by HRH PrincessFreestarr 3

You are travelling in a sealed box car that left the station several minutes ago and is accellerating smoothly, at a constant accelleration of 0.1 G.

You're bored so you tie the ballon to the center of the floor with 1 meter of string.

Does the balloon float straight up, lean toward the back or lean toward the front? Why? If it leans, how much?

2007-07-05 08:19:10 · 10 answers · asked by Doug S 4

When you ask someone what is gravity the standard answer is the force that binds us to this planet or from the plebes ..WOT HOLDS US DOWN ???? I want to know what is the specific force called Gravity as light is a radio particle what is Gravity ? as water is a chemichal combination H20 . What is Gravity we all know what Newton said it was but what do you think it is .

2007-07-05 07:54:48 · 22 answers · asked by vortash2 2