Physics - July 2007

1) Answer all that are correct-
You run and jump on a swing. During which of the following motions is the total momentum of you and the swing conserved?
running at the swing (and accelerating)
jumping on the swing (the "collision" between you and the swing)
swinging up on the swing
swinging down on the swing
2)Answer all that are correct-
You run and jump on a swing. During which of the following motions is the total mechanical energy of you, the swing, and the Earth conserved? (Assume that the swing is well made so friction can be ignored.)
running at the swing (and accelerating)
jumping on the swing (the "collision")
swinging up on the swing
swinging down on the swing
3) Momentum conservation occurs whenever
the net external force on the objects is zero
the work on the objects is zero
two objects are stuck together
two objects are pulled apart

2007-07-21 20:53:27 · 3 answers · asked by Anonymous

1. suppose a free falling object is equipped w/ an odometer, would the readings of distance fallen for each sec indicate equal or different falling distances for successive seconds?

2. for a free falling object dropped from rest, what's the acceleration at the end of the 5th sec of fall? 10th sec?

3. by how much does the speed of a ball decrease each second while ascending when it's thrown up?
w/out air resistance, how much does it increase each sec while descending? how much time is required for rising compared to falling?

4. which ball will have a greater speed when it strikes the ground below? one thrown up or down with the same initial speed. [air resistance is negligible]

5. answer question 4 where air resistance is not negligible?

2007-07-21 20:40:57 · 1 answers · asked by sheran g 1

2007-07-21 20:16:27 · 3 answers · asked by iLOVEmanila 2

please explain

2007-07-21 20:07:49 · 8 answers · asked by Sheridan G 2

2007-07-21 20:02:37 · 4 answers · asked by Sheridan G 2

what is the impact speed when a car moving at 100 km/h bumps into the rear of another car traveling in the same direction at 98 km/h

2007-07-21 19:55:00 · 2 answers · asked by daisy 2

My NNF would be corn starch and water, shot with a small caliber rifle round, maybe a .22. Would it stop the bullet?

I think Im going to try it but I want to hear from the people.

2007-07-21 19:16:18 · 5 answers · asked by Mike D 2

Here's a challenge problem I thought up relating to interstellar travel at relativistic speeds.

Your spaceship is in Earth orbit. You want to journey to Proxima Centauri, which is 4.22 light-years away, then return to Earth. Your ship is capable of traveling at any speed between 0 and c, the speed of light. If you make the journey at close to the speed of light, time dilation will cause many years to pass back on Earth. However, if you travel extremely slowly, the trip will take a long time.

What fraction of the speed of light do you travel to minimize the amount of time that passes on Earth during your round trip to Proxima Centauri?

10 points to the first correct answer!

2007-07-21 19:03:27 · 4 answers · asked by lithiumdeuteride 7

...then is it possible that they could turn blind?
please answer with scientific information if you can, i gotta learn a lot about this

2007-07-21 18:52:15 · 2 answers · asked by orassen 1

1. can an automobile with a velocity toward north simultaneously accelerate toward the south?
2. can an object reverse its direction of travel while maintaining an constant acceleration? if so site examples if not explain why?
3. starting from rest one car accelerates to a speed of 50km./hr. and another car accelerates to a speed of 60 km./hr. can you say which car underwent greater acceleration? why?
4. Cite an example of something that undergoes acceleration while moving at constant speed. Can you also give an example of something that accelerates while traveling at constant velocity? explain
5. cite en example of something with a constant speed that has a varying velocity? cite also an example that has varying speed that has constant velocity. explain
6.can an object be moving with zero acceleration? cite example Can an object accelerate with a speed of zero?if so give example
7can you cite an example wherein the acceleration of the object is opposite in direction of its velocity?

2007-07-21 18:37:33 · 2 answers · asked by Anonymous

2007-07-21 18:37:22 · 4 answers · asked by samuraihero1992 2

v=u+at which means ds/dt=u+at. Then integrate both sides and s=ut+0.5at^2+c where c is a constant but why is c always left out when we have a reference point?

Side question also related to projectile motion:
How does air resistance affect the range of the motion?
How does the angle change ,compared to the angle without air resistance to reach a point, when there is air resistance to reach the similiar point?

2007-07-21 18:17:26 · 7 answers · asked by Anonymous

why using high voltage transmission can reduced the resistance?please give me a clear explanation...

2007-07-21 16:26:58 · 3 answers · asked by Daireen 2

1. give examples of optical instruments that uses a convex or converging lens?
2. how do lenses change the direction of light rays and form images?

2007-07-21 16:07:16 · 3 answers · asked by beibi anghell 1

2007-07-21 14:48:05 · 7 answers · asked by amazed we've survived this l 4

can some please tell me the differance between ultrasound and ultrasonic.

2007-07-21 14:40:32 · 2 answers · asked by dcrc93 7

1) A 10 kg piece of putty going 3 m/s hits and sticks to a 5 kg puck that is free to slide on the ice. How fast is the puck/putty combindation going immediately after the collision?
3 m/s
6 m/s
2 m/s
45 m/s
2) Answer all that are correct-
You run and jump on a swing. During which of the following motions is the total momentum of you and the swing conserved?
running at the swing (and accelerating)
jumping on the swing (the "collision" between you and the swing)
swinging up on the swing
swinging down on the swing
3)Answer all that are correct-
You run and jump on a swing. During which of the following motions is the total mechanical energy of you, the swing, and the Earth conserved? (Assume that the swing is well made so friction can be ignored.)
running at the swing (and accelerating)
jumping on the swing (the "collision")
swinging up on the swing
swinging down on the swing

2007-07-21 14:39:26 · 4 answers · asked by whitmeeeee 1

I've heard a lot about an experiment called "Shroedinger's Cat" while I've been reading up on theoretical physics, but I have no idea what the experiment is. Could anyone shed some light?

2007-07-21 14:31:22 · 7 answers · asked by Anonymous

2007-07-21 13:54:42 · 4 answers · asked by jjtmm 2

2007-07-21 13:40:06 · 7 answers · asked by jjtmm 2

i like helium

2007-07-21 13:13:56 · 2 answers · asked by Anonymous

hi, can someone please tell me how is it that a whistle makes noise? please explain in simple terms, what is the concept in physics that is involved in whistles? i have studied conceptual physics but no calculational physics, thanks!

2007-07-21 13:03:06 · 1 answers · asked by questionhere 2

WHAT MATHEMATICIAN, CITED EARLIER, THAT THE LIFE TIME CAPACITY OF THE AVERAGE MEMORY IS UP TO ( ONE HUNDREDTRILLION) BITS. THEN WHO CAME A LONG TO DISTINGUISH AND JUST AS PLAUSIBLE PUT THE FIGURE AT (280 QUINTILLION) AND BY DOING SO THOUGHT THAT NOTHING IS TRULY FORGOTTEN, BUT WE KEEP VERY LITTLE IN OUR ACTIVE MEMORY, AND YET STILL WE WOULD HOLD SEVERAL BILLION TIMES MORE INFORMATION THAN A LARGE CONTEMPORARY RESEARCH COMPUTER.

2007-07-21 13:01:52 · 2 answers · asked by aprilmacfadden 3

I'm trying to figure out what constitutes a minute, how was the first minute determined? i know that someone did not just count to 60 and say "that's a minute". does anyone know where i could find resources on this topic? or could provide me with a starting point?

thanks so much

2007-07-21 12:42:52 · 5 answers · asked by B E A * 2

2007-07-21 11:10:47 · 17 answers · asked by Anonymous

2007-07-21 09:53:43 · 6 answers · asked by foghnanross 2

2007-07-21 09:11:06 · 4 answers · asked by msmith1515 1

2007-07-21 07:29:01 · 0 answers · asked by mualim 1

2007-07-21 07:10:35 · 3 answers · asked by hope 5

and also,we know tht the poles of the earth were changed in the history of earth but in wht way tht would happen???

thnx a bajillion!

2007-07-21 05:29:00 · 2 answers · asked by RaZoR 2