Physics - November 2006

In bench pressing 1.0 x 10^2 kg, a weight lifter applies a force of 1040 N. How large is the upward acceleration of the weights during the lift?

2006-11-01 14:16:04 · 2 answers · asked by yoo whoo 1

Is a machine still a Perpetual Motion one if you have to "start it". I mean only once until you actual stop it. Like if it was a car that you had to start, but after that it just kept going and going, like that energizer bunny?

2006-11-01 14:08:20 · 8 answers · asked by esage321 2

An object hanging in the air, caused a scale to balance at 0.0554 kg. When the object was submerged in water, the scale balanced at 0.0370 kg.

1-What is the volume of the object? (density of water = 1000 kg/m3)

2-What is the density of the object?

2006-11-01 14:05:48 · 1 answers · asked by Anonymous

If let say 1 mole of water occupies 18cm^3 and one molecule is average at the center of a small cube, what will be the length of the sides of the small cube? What will be the diameter of the molecule compare with that length?

2006-11-01 13:57:32 · 1 answers · asked by jai 1

2006-11-01 13:53:50 · 7 answers · asked by Anonymous

A playground merry-go-round of radius 2.00 m has a moment of inertia I = 230 kgm2 and is rotating about a frictionless vertical axle. As a child of mass 25.0 kg stands at a distance of 1.00 m from the axle, the system (merry-go-round and child) rotates at the rate of 14.5 rev/min. The child then proceeds to walk toward the edge of the merry-go-round. What is the angular speed of the system when the child reaches the edge?

2006-11-01 13:49:35 · 1 answers · asked by Anonymous

...turn and electric generator. For maximum power generation, shoul de turbine blades be design so that the water is brought to a dead stop, or so that the water rebounds?

2006-11-01 13:46:24 · 2 answers · asked by alanis118 1

I was thinking about designing and building a radio controlled submarine for fun but I am wondering if it will be able to pick up radio waves from up to 20 feet under fresh water. If anybody knows anything about this subject I would appreciate some feedback.
thanks, Mike

2006-11-01 13:17:23 · 5 answers · asked by mikeytrav 1

I've tried the following problem and I keep getting the wrong answer. I'm just hoping someone can help me figure this one out.

In exercise physiology studies, it is sometimes important to determine the location of a person's center of gravity. This can be done with the arrangement shown in Figure P8.67. A light plank rests on two scales that read Fg1 = 450 N and Fg2 = 310 N. The scales are separated by a distance of 2.00 m. How far from the woman's feet is her center of gravity?

Thanks a lot guys!

2006-11-01 13:16:56 · 5 answers · asked by Anonymous

I'v tried to figure out why this wouldn't work but I don't Know enough math so here goes. If you were to take a chamber filled with water and put a float at the bottom conected to an arm to capture the energy of the rise up the chamber you would have one equation for the amount of power created.
Next you push the object over (possibly still floating) then close off the chamber so you don't have more water loss. Next you would let the object fall, Maybe connected to a pump to fill the water chamber back up.
I know all the power that you get from the fall needs to go back to filling the chamber plus some of the power from the boyancy because of inefficiencies but it seems that my outher two actions of moving my weight-float back and forth would not use all the power that could be created.
The reason I think this might work is because you kind of turn gravity sideways. all the water wheals that I could find kept everything submurged and did not remove it from the water midum.

2006-11-01 13:04:22 · 4 answers · asked by John K 1

A. an "s" orbital
B. a "p" orbital
C. a combination of two different "p" orbitals.
D. a combination of an "s" and a "p" orbital

2006-11-01 12:46:24 · 3 answers · asked by Anonymous

My Daughter asks short questions that involve long answers, and her latest was "When you are riding in a car, how come the telephone poles are moving slow when you look out the front window, and moving much faster when you look out the side window?"
The Answer is The theory of relativity, but I'm having trouble explaining it to her so she can understand it. Any Help?
Thanks,
Sparky.

2006-11-01 12:28:08 · 17 answers · asked by sparky_the_perv 3

a uniform rod of length L is free to pivot around an axis through its upper end. if it is released from rest when horizontal, at what speed is the lower end moving at its lowest point?

(Hint: the gravitational potential energy change is determing by the change in height of the center of gravity.)

2006-11-01 11:33:55 · 1 answers · asked by Trevor M 1

okay ladies and gentlemen, i need some help with homework. I have no idea how to do this physics problem, i would appreciate some help. here it is...

a painter (mass 61kg) is walking along a trestle, consistiing of a uniform plank (m=20kg l= 6.00m) balanced on two saw horses. each is placed 1.40 m from an end of the plank. a pain bucket (m=4.0kg,diameter 28cm) is placed as close as possible to the right hand edge of the plank while still having the whole bucket in contact with the plank.

question:

a. how close to the right hand edge of the plank can the painter walk before tipping the plank and spilling the paint?

b. how close to the left hand edge of the plank can the painter walk before causing the plank to tip? (hint: as the painter walks toward the right handed edge the plank tips clockwise, what is the force acting upward on the plank from the left hand sawhorse support?)

2006-11-01 11:29:58 · 2 answers · asked by Trevor M 1

An object is dropped from a height of 50m, on a certain planet it took 5 seconds to reach the ground. What is the weight of the object on the planet if its weight on earth is 35N?

2006-11-01 11:06:26 · 5 answers · asked by Anonymous

2006-11-01 10:57:49 · 4 answers · asked by Elizabeth s 1

i need this answer for my next test.

2006-11-01 10:57:07 · 4 answers · asked by cute girlz 2

A projectile is launched with an initial speed of 18.5 m/s at an angle of 74 degrees above the horizontal.
What are the x and y components of the initial velocity?

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What are the x and y components of a vector in the xy plane if its direction is 290° counterclockwise from the positive x axis and its magnitude is 6.3 units?
Ax = units
Ay units

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2006-11-01 10:56:07 · 1 answers · asked by ckielblock18 1

how does freezing point and melting point help us identify a substance?>

2006-11-01 10:46:58 · 12 answers · asked by Anonymous

If water drains counter clockwise in the northern hemisphere, and clockwise in the souther hemisphere, what will we see with draining water directly at eh equator??

2006-11-01 10:42:38 · 3 answers · asked by Anonymous

If a vector problem tells you that the flight instruments show a direction of 30 degrees South of West, is that direction a part of the vector of the velocity of the plane relative to the air OR a part of the vector of the velocity of the plane relative to the ground?

2006-11-01 10:38:06 · 1 answers · asked by c90 4

I have worked out this problem and got .77 for part b and that is wrong. I have asked this question already and got some tips, but they aren't working. Can someone work the second part of this problem and tell me how you worked it out?


A 2.50 g bullet, traveling at a speed of 425 m/s, strikes the wooden block of a ballistic pendulum, such as that in Figure 7.14. The block has a mass of 265 g.


http://i21.photobucket.com/albums/b272/Cajunboiler/worstthingever.gif



(a) Find the speed of the bullet/block combination immediately after the collision.


3.9 m/s
(b) How high does the combination rise above its initial position in meters?



Can someone help with part b?

2006-11-01 10:35:51 · 4 answers · asked by Confused 1

2006-11-01 10:31:06 · 13 answers · asked by Anonymous

2006-11-01 10:24:59 · 2 answers · asked by Adamgenius 2

(2 billiards balls)
Using Physics principals, and using as few steps as possible.

2006-11-01 10:13:43 · 7 answers · asked by Anonymous

Does the football become lighter and easier to throw?

2006-11-01 09:58:50 · 10 answers · asked by Anonymous

When Elipses happen on the earth because of an amazing coincidence, how to calculate the angular diameters in radians of the sun and the moon, as seen on earth.

2006-11-01 09:50:02 · 1 answers · asked by nice_ girl 1

.30 m and mass of 1.1 kg is rotating at 93.6 rad/s.

What torque is necessary to stop the tire in 1.72s in uits of N.m?

2006-11-01 09:44:48 · 2 answers · asked by Anonymous

Flywheel shaped like a solid cylinder w/ radius of 0.4999 m and mass of 10.1 kg can be brought to an angular speed of 5.88 rad/s in 0.531 s by a motor exerting constant torque. When the motor is turned off, the flywheel makes 26.8 rev before coming to rest because of friction (assumed constant during rotation).

What percentage of the power genrated by the motor is used to overcome friction????

2006-11-01 09:41:58 · 2 answers · asked by Dee 4

Our high school had a person come in and do a workshop today, involving bending spoons with your mind (I'm not joking).

It had something to do with relaxing your mind, thinking about a positive image, and mentally picturing the spoon bending. Some people who concentrated very intently actually bent it (I'm not on drugs).

What's the scientific explanation for this?

2006-11-01 09:38:44 · 9 answers · asked by Anonymous