Physics - March 2007

2007-03-28 09:29:26 · 11 answers · asked by diamondeyesx 3

she begins to rotate at a much faster rate. When she stretches out her arms once again, she rotates more slowly. Which of the following best explains this phenomenon?

This is what I have to chose from

When the skater's arms are out, she has more air resistance, so she moves more slowly.

The act of bringing her arms closer to her body pushes her around more quickly.

With her arms together, she has more weight pressing down on a smaller area, which allows her to move faster.

With her arms outstretched, her moment of inertia is larger, so when she brings them in, her angular velocity much increase due to the conservation of angular momentum,

She must do work to bring her arms into her body, and so that work goes into increasing her angular velocity.

Can anyone help me please?

2007-03-28 09:15:57 · 5 answers · asked by Sesily E 1

What is the resultant electric field at the -8mC charge? What is the force on q3 from this field?

q1= +6mC
q2= +10mC
q3= -8mC
d 1to2= 10cm
d 2to3= 20cm


i have the answer, but i dont understand it, if someone could show me how to do it, id be greatful!

2007-03-28 09:06:06 · 2 answers · asked by Anonymous

A 1000 N uniform boom is supported by a cable perpendicular to the boom, as in Figure P8.26. The boom is hinged at the bottom, and a 1900 N weight hangs from its top.
(see image link below)
http://www.webassign.net/sercp/p8-26alt.gif
(a) Find the tension in the supporting cable
(b) Find the components of the reaction force exerted on the boom by the hinge.
-to the right_________N
-upward ___________ N

2007-03-28 08:58:01 · 1 answers · asked by Emma 1

2007-03-28 08:53:33 · 4 answers · asked by lalonso 1

Hey everyone, I am really stumped on this question for Grade 12 Physics. Just looking for a formula or a process which I can use to find the answer, thanks :)

A 0.4kg cue ball hits a stationary 0.30kg billiard ball so the cue ball deflects with a speed of 1.2 m/s at an angle of 30 degree from its original path. Calculate the original speed of the cue ball if the billiard ball ends up traveling at 1.5 m/s.

I have...
m1 = 0.4kg
m2 = 0.3kg

v'1 = 1.2 m/s
v'2 = 1.5 m/s

v1 = ?
v2 = 0 m/s

Thanks for help

2007-03-28 08:48:25 · 6 answers · asked by Amanda V 1

Starting from rest, a child on a sled slides 20m down an icy hill that is inclined at 28 degrees. The coefficient of kinetic friction for the sled on ice is .09. After the child slides down the hill, they slide on level ground on gravel with a coefficient of kinetic friction of .33. The child and the sled together are 18kg. How far from the base of the hill does the child on the sled slide before coming to rest? Any help would be appreciated!!!

2007-03-28 08:20:33 · 4 answers · asked by Anonymous

I need help with this physics question:

A 4.0 kg bar of gold at 200°C is dropped into a tub that contains 50L of water at 20°C.
- What is the tempreature of the mixture when it come to equilibrium?
- How much heat did the gold bar lose?

any help is appreciated!

2007-03-28 08:08:10 · 3 answers · asked by Anonymous

2007-03-28 08:05:23 · 3 answers · asked by Anonymous

I conducted this experiment where you use two optical lenses to build a simple microscope. I need to describe what I observed with my microscope, but I'm not sure if i observed correctly since it was hard to focus on my eyes.
Is the object supposed to look real or virtual? upright or inverted? reduced or enlarged?
I know it looked inverted and definitely enlarged.

2007-03-28 08:05:06 · 3 answers · asked by Anonymous

what are two types of energy other than potential and kinetic that can be converted directly into another type

2007-03-28 08:00:22 · 2 answers · asked by everlife90210 1

2007-03-28 07:41:47 · 2 answers · asked by Anonymous

apart. How far apart will the interference peaks be on a screen 1.1 m away? [Hint: first find the wavelength of the neutron.]

2007-03-28 07:18:10 · 2 answers · asked by Rita Z 1

2007-03-28 07:16:40 · 2 answers · asked by Rita Z 1

In the cylinder with a radius R=0.2m with an inertia moment I=0.1kgm^2 it is rolled a cord in the bottom of which it is hanged up a solid with a weight 0.5 kg. Before that the cylinder started rolling, the solid was standing in the height h=1m from the floor. Find:
a) The time in which the solid will reach the floor.
b) The kinetic energy in the moment when the solid touches the floor.
c) The tension (T) of the cord. ( Do not include in the result the frictional forces)
Answers: t=1s, Kinetic energy=0.81J, T=4.1N

2007-03-28 07:14:07 · 1 answers · asked by Crystal 3

when its got trillions of atoms in it pathway before it reaches me?

2007-03-28 07:07:49 · 6 answers · asked by Anonymous

A pendulum swings back and forth with a period of 0.5 s. what is the lenght of the pendulum arm?
somebody please help i just started this yesterday and really don't understand.

2007-03-28 07:07:28 · 1 answers · asked by star wars freak 2

2007-03-28 07:03:56 · 2 answers · asked by jasmine m 1

Two balls are approaching each other for a head on collision. Ball #1 has a velocity of 8.9 m/sec and Ball #2 has a velocity of -11 m/sec.

Part A.) What is the velocity of the center of the two ball if they both have the same mass?

Part B.) What is the velocity of the center of the mass of the two balls if the mass of Ball #1 is 4 times as big as the mass of Ball #2 ?

2007-03-28 07:00:14 · 2 answers · asked by por_ti_a_17 2

2007-03-28 06:25:29 · 2 answers · asked by The Ponderer 3

Plz explain, but not longer than a page, and don't send any links. thx

2007-03-28 06:24:34 · 4 answers · asked by The Ponderer 3

explain in terms of energy transfer (dissipation) why sound becomes fainter further away

2007-03-28 06:12:17 · 3 answers · asked by Rushton 3

A 63.0kg astronaut is on a space walk when the tether line to the shuttle breaks. The astronaut is able to throw a 10.0kg oxygen tank in a direction away from the shuttle with a speed of 12.0m/s, propelling the astronaut back to the shuttle.

2007-03-28 06:11:16 · 1 answers · asked by Anonymous

that light, gavity and other waves are all related, but how? and on the lighter side can any of you smart sweetys get gavity off of my butt? its getting to big, haha thanks guys

2007-03-28 06:07:14 · 3 answers · asked by ♥lois c♥ ☺♥♥♥☺ 6

however, the can opener does only 500 joules of work in opening the can.

What is the efficiency of the can opener?

Please explain to me.

2007-03-28 06:02:08 · 3 answers · asked by marina 1

Is it relevant to thin plate theory by Lagrange?

2007-03-28 05:46:41 · 1 answers · asked by Bernard Lee 1

2007-03-28 05:38:30 · 4 answers · asked by marina 1

Ok I know roughly what gravity is, but can you please tell me what it is in a UNDERSTANDABLE detail. (I am an eager yet young student and Im still in high school.

Also if there is only one thing in the Universe, and nothing else, would there still be gravity? Forgetting about the forces inside that object, would there be gravity or not.

Finally can u please explain the "big yawn" or expanse of the Universe to me in a nutshell, in easy language relating to gravity, forces...

Sources will be great! THanks!

2007-03-28 05:31:35 · 5 answers · asked by ღ♥ღ latoya 4

Please refer to my previous post, and give me some feedback. Like I said before, it is just a theory.

http://answers.yahoo.com/question/index;_ylt=AnQkkPy7uUZ0nUZsPFCCUWbsy6IX?qid=20070328084652AAxgAtq

2007-03-28 05:29:31 · 3 answers · asked by ? 4

If I go backwards in time, the theories are that I would meet a past me, because it is like writing in a book, it's already been written. However if I go forward in time, would I meed my future self, or would I be unwritten so to speak in that time as I have made my pen skip forward to the next page?

Basically, do we already exist in the future like we already have in the past? Any theories for this?

2007-03-28 04:55:53 · 8 answers · asked by Luis 6