Physics - October 2007

I hear alot of good things based on string theory, however i would like to know what bad experimental data evidence has already been found or may be found in the future. Such as at astronomical scales and at quantum scales with current technology or future technology. I am aware of the general bad points, such as too complex etc. Thanks

2007-10-27 12:37:31 · 1 answers · asked by Anonymous

An 80 N box is pulled 20 m up a 30o Incline by an applied force of 100N that point upward, parallel to the incline. If the coefficient of kinetic friction between box and incline is 0.220, calculate the change in the kinetic energy of the box.

2007-10-27 12:26:59 · 1 answers · asked by info2know 3

a cat running a horizontal surface jumps off a roof 5.8 meters away. he grabs a building 3.7 meters below his starting point. what is his initial velocity?

2007-10-27 11:53:18 · 2 answers · asked by magna1211@sbcglobal.net 1

about electromagnetic waves and general situations of using electromagnetic

2007-10-27 11:36:43 · 2 answers · asked by Anonymous

2007-10-27 11:30:56 · 16 answers · asked by Bob L 1

A racecar traveling at 44 m/s is uniformally accelarated to a velocity of 22 m/s over and 11 second interval. What is the displacement during this time?

Steps please.

2007-10-27 10:24:04 · 2 answers · asked by kickitup21 1

You weight 625 N on earth. What would you weight on Venus? Venus' mass is 4.88 x 10^24 kg and it has a radius of 6.07 x 10^6 m.

2007-10-27 09:54:06 · 1 answers · asked by ? 2

2007-10-27 09:48:31 · 1 answers · asked by Anonymous

about physics

2007-10-27 09:32:19 · 2 answers · asked by Anonymous

Ignoring U, and assuming Q=0

A spring has spring constant k=100N/m

a) Find displacement y produced by external force F=(-10)N.

b) Find total mechanical energy of mass+spring if oscillating with amplitude 10cm.

c) Find transfer by working for mass+spring when you move spring from 15cm to 5cm, assuming no change in kinetic energy.

I get:

a) (-0.1)m

b) 0.5J

c) (-1)J

I would just like some feedback on these answers thank you.

2007-10-27 09:11:39 · 1 answers · asked by eazylee369 4

avg. velocity = (initial velocity + final velocity) / 2

2007-10-27 09:02:12 · 3 answers · asked by James 1

2007-10-27 08:23:07 · 9 answers · asked by G 5

2007-10-27 08:16:46 · 3 answers · asked by kishen p 2

2007-10-27 08:00:47 · 4 answers · asked by illuminati46 2

can you also show how to do it?

2007-10-27 07:54:43 · 1 answers · asked by need help 2

I do know that standing waves is about adding 2 waves onto each other, but what is constant for standing waves to occur?

how do we create standing waves? by varying the frequency?

2007-10-27 07:31:24 · 4 answers · asked by Anonymous

I want to know how to figure out speed, so I was wondering if anyone knew a formula in how to figure it out? If not, is there a website that it will figure it out for me? Thanks!

2007-10-27 07:19:43 · 8 answers · asked by Sir_Knows_Alot 1

Doug pushes a 5.30 kg crate up a 2.10-m-high 20 degree frictionless slope by pushing it with a constant horizontal force of 22.0 N. What is the speed of the crate as it reaches the top of the slope? Solve this problem using work and energy, and then using Newton's laws.

2007-10-27 07:14:32 · 1 answers · asked by rochesmk 2

2007-10-27 07:11:51 · 20 answers · asked by losing my mind 2

if Doug leaves home on a trip to the lake that takes him to a position of 80km [W] of home, what is his displacement? do you know the distance that he traveled?

*ok. i really don't understand this question. can you explain the steps you took to solve this or any other displacement question?/
thanks!

2007-10-27 07:11:06 · 2 answers · asked by Bella! 3

If a plane is traveling at takeoff speed on a conveyor belt, and the belt is matching that speed in the opposite direction, can the plane take off?

Discuss

2007-10-27 07:09:30 · 8 answers · asked by the saint 2

above the Earth's surface if its mass is 1500 kg.
N (toward the earth)

2007-10-27 07:08:26 · 3 answers · asked by cindy d 4

Four railroad cars, each of mass 2.80 104 kg, are coupled together and coasting along horizontal tracks at speed vi toward the south. A very strong but foolish movie actor riding on the second car uncouples the front car and gives it a big push, increasing its speed to 4.15 m/s south. The remaining three cars continue moving south, now at 1.80 m/s.

2007-10-27 06:41:05 · 1 answers · asked by Anonymous

first i can be wrong because i am 14.my question is why cant we turn oxyzen in solid?we can turn oxyzen liquid by an extrem force like freezing.then why cant we turn it into solid? and is there any thing or power or energy which is more faster than light?and why? if i have done any wrong thing please dont insult me.and if you liked my question you can give me a star.thanks to everybody and pls answer this question.

2007-10-27 06:35:45 · 7 answers · asked by Anonymous

A merry-go-round of radius R, is rotating at constant angular speed. The friction in its bearings is so small that it can be ignored. A sandbag of mass is dropped onto the merry-go-round, at a position designated by r. The sandbag does not slip or roll upon contact with the merry-go-round.
Rank the following different combinations of m and r on the basis of the angular speed of the merry-go-round after the sandbag "sticks" to the merry-go-round:
1.) m =10kg, r=.50
2.) m =40kg, r=.25
3.) m =10kg, r=.1.0
4.) m =20kg, r=.25
5.) m =10kg, r=.25
6.) m =15kg, r=.75

2007-10-27 06:34:31 · 3 answers · asked by Nik 1

1. The entropy of the Universe increases for all natural processes.

2. If two bodies are in thermal equilibrium with a third body, then they are also in thermal equilibrium with each other.

3. Ein - Eout = ΔEsystem

4. It is impossible to construct a device that, operating in a cycle, will produce no effect other than the extraction of heat from a reservoir and the performance of an equivalent amount of work.

5. It is impossible to construct a device that, operating in a cycle, will produce no effect other than the transfer of heat from a lower-temperature reservoir to a higher-temperature reservoir.

6. The total entropy of an isolated system that undergoes a change cannot decrease.

2007-10-27 06:22:51 · 2 answers · asked by Anonymous

i am 13 years old and people are always telling me how smart I am because I learned to read when I was 13 months old, and that I understood M-Theory when i was 7, stuff like that, Also I am really interested in science, but I've no desire to work in that field, I understand time travel and I have built small machines that can exceed my own running speed since i was about 9, what are the qualities of a person like Newton or some of those other really smart people? I need to know how old some of you people are, and how old you were when you started showing signs of being smart! And dont tell me I am the only one here who is under 30 and understands M-Theory because @ my school I have teachers that dont get it!

2007-10-27 06:22:25 · 11 answers · asked by shacka t 2

Does increasing mass increase speed of projectile?
Does increasing mass increase distance forever?
How does the increased force from the added mass transfer throughout the entire system?

2007-10-27 06:11:47 · 2 answers · asked by Anonymous

A projectile has mass 21 kg and is fired at a 60 degree angle above the horizontal with a speed of 80 m/s. At the highest point of its trajectory, it explodes into 2 pieces, one of which falls straight down with no initial speed. The 2 pieces have equal mass, and air resistance can be ignored. Find the distance from the point of firing that the other piece strikes assuming a level terrain, and find how much energy was released during the explosion.

2007-10-27 06:02:49 · 2 answers · asked by Red_Wings_For_Cup 3

Why do physicists continue to pursue answers to sigma when if you use Eeinstiens theories and equations rather than the outdated Newtonian gravitational equations, there is no need for Dark Matter ot explain sigma at all.

2007-10-27 06:00:32 · 4 answers · asked by DannyB 2