Physics - October 2007

A wiehgt lifter can lift 150kg vertically at a constant speed to a position 2m over his head.

so because he is lifting it at a constant speed, when you draw the free body diagram, you know that the normal force and the weight should be the same (due to equilibrium). So does that mean if you get the sum of the work done by the weight and the normal force, it should be ZERO?

2007-10-23 06:49:06 · 6 answers · asked by Anonymous

Hey, a couple of weeks ago I did a physics homework research about the dangers of wireless technology, and I found out quite worrying stuff. It's really annoying because I have wireless internet in my house, and I keep on thinking how the microwaves race through my brain, it's so annoying, could someone please tell me what kind of damage can wireless technology do to me, and how can I prevent it or whatever...

2007-10-23 06:23:48 · 9 answers · asked by summer_lov3 3

On what temperature is water cooling down the slowest (or better, the temperature range)?

And what about air?

Thanks

2007-10-23 05:58:48 · 6 answers · asked by Anonymous

Well... wtihout involving into other... functionals... or maybe we better consider them too... Well... I am hoping your answers will come handy...

2007-10-23 05:54:13 · 3 answers · asked by Robert M Mrok (Gloom) 4

Does it help at all or is it like pulling yourself out of a swamp by your own hair? An explanation and/or reference would be nice.

2007-10-23 04:39:14 · 7 answers · asked by Puppy Zwolle 7

It happens at least once a day. I am driving down the street and a light will go off. Is it energy related? What the hell!

2007-10-23 04:37:05 · 8 answers · asked by Bambina 2

Electric toothbrushes can be effective in removing dental plaque. One model consists of a head 1.10 {\rm cm} in diameter that rotates back and forth through a 70.0^\circ angle 7600 {\rm times}/{\rm minute}. The rim of the head contains a thin row of bristles

2007-10-23 04:16:22 · 1 answers · asked by scott.leever 1

2007-10-23 02:14:50 · 1 answers · asked by Anonymous

Roy has a mass of 60kg. Laurie has a mass of 65kg. they are 1.5m apart.
a) what is the magnitude of the gravitational force of the earth on Roy?
b)what is the magnitude of Roy's gravitational force on the earth?
c)what is the magnitude of the gravitational force between Roy and Laurie?
d)what is the magnitude of the gravitational force between Laurie and the sun?

i would be happy if some1 could just walk me thru it by showing steps. thank you.

2007-10-23 00:38:36 · 2 answers · asked by Anonymous

2007-10-22 21:59:12 · 6 answers · asked by lulu 1

WATER=TWOHYDROGEN ATOM=ONE OQYGEN ATOM AND BOTH ARE PRESENT IN OUR ENVIRONMENT THEN WHY SHUOLD THEY DO NOT COMBINE TO MAKE A CONTIUOUS RAIN ON EARTH

2007-10-22 21:15:58 · 3 answers · asked by afzal a 1

a person looks at her reflection at the concave side of a shiny spoon. is it right side up or inverted? does it matter how far his face is from the spoon? what if he looks in the convex side?

2007-10-22 20:34:46 · 2 answers · asked by wizard21 1

2007-10-22 18:31:18 · 7 answers · asked by paper12 2

Can you please list some and what stores they can be found in? Thank-you.

2007-10-22 18:30:52 · 3 answers · asked by RozeRouge 2

Why is it that when photons fall on atoms, it would be absorbed only if it posses specific energy corresponding to the energy differences between orbitals, whereas for Compton effect, it can be scattered, losing part of its energy only.

2007-10-22 17:22:54 · 2 answers · asked by Anonymous

By "ideality", I specifically mean "scientific ideality"( I could not fit Q-box limits w/o the shortening)

2007-10-22 17:20:54 · 2 answers · asked by Anonymous

In a lab experiment, we ran up stairs and figured out our power by calculating work done divided by the time it took. Work=gravitational potential energy. The question is...is this a true measure of your body power?

2007-10-22 17:09:01 · 6 answers · asked by Anonymous

2007-10-22 16:36:36 · 2 answers · asked by Memo 3

if 2 really good doctors switched your blood with a bllod like substitue one doctor pumping out blood and the other pumping in.....


would you live

2007-10-22 16:22:12 · 14 answers · asked by davon tremaine foots a.k.a D.T.F 3

A helicopter is travleing at 40 m/s at a constant altitude of 100 m over a levle feild. If a wheel falls off the helicopter, w/ what speed will it hit the ground?
-40 m/s
-50m/s
or
-60 m/s

2007-10-22 16:19:56 · 4 answers · asked by Anonymous

different question below:

If the magnitude of the vector component equals zero, what is the magnitude of the other component?

2007-10-22 16:09:31 · 1 answers · asked by jalisamarie12 1

What is the difference between virtual image created by a converging lens to the one created by a diverging lens?

2007-10-22 16:08:42 · 1 answers · asked by To-the-Stars 4

which of the four forces acts over the longest distance?

2007-10-22 16:06:33 · 1 answers · asked by hm 2

2007-10-22 15:57:25 · 2 answers · asked by Anonymous

so i have to have th things float at first then sink to the bottom when i squeeze it in water. any ideas?

2007-10-22 15:41:04 · 1 answers · asked by Laura Block 4

Caitlin is playing tennis against a wall. She hits the tennis ball from a height of 0.5 m above the ground with a velocity of 20.0 m/s at an angle of 15.0° to the horizontal toward the wall that is 6.00 m away. a) How far off the ground is the ball when it hits the wall? b) Is the ball still traveling up or is it on its way down when it hits the wall?

2007-10-22 15:25:23 · 1 answers · asked by Anonymous

2007-10-22 15:21:15 · 1 answers · asked by chess_e4_pr 1

consider a classroom 10 m long by 6 m wide by 4 m high at "room temp" 20 degrees celcius and 1 atmosphere. What is the mass of room air?if all air was replaced by helium what would be the weight of helium in the room?

2007-10-22 15:16:31 · 1 answers · asked by Anonymous

what color would i get if i pass light from a light bulb through a red filter and then through a green filter?

2007-10-22 15:08:50 · 7 answers · asked by Anonymous

you are driving a car 50 miles per hour. a fly is sitting on your head.what is the speed of the fly if the reference point is your nose?
i need help with my science homework.

2007-10-22 15:06:02 · 6 answers · asked by nirvana 1