Physics - November 2007

If a satellite in circular orbit is observed to have a speed of 5620 m/s at a eight of 8.73 x 10^6 m above the surface of a planet of radius 1.02 x 10^7 m, what is the mass of the planet?

2007-11-13 12:08:48 · 6 answers · asked by Anonymous

The blovk weighs 1.22 x 10*4 N. Assuming there is no friction what is the maximum angle that the slope can make with the horizontal if the machine is to able to complete the task?

2007-11-13 12:07:28 · 1 answers · asked by life 2

I've heard, that for EACH nuclear explosion, there's a statistical chance the WHOLE atmosphere will blow up and thus eliminating mankind. It was estimated that the chance was once in a million or so. But i heard that number many years ago. What's the current view on this?
Maybe the chance is 1 in only 1000 or so?

2007-11-13 11:46:31 · 1 answers · asked by · 5

ok well i dont know the acceleration, or the initial velocity. I have to find out both values. Which equations can i use?

2007-11-13 11:05:06 · 1 answers · asked by mephisto 5

How high will an M4 bullet go? If I shoot an M4 straight up in the air, how high up will it go?

2007-11-13 11:02:59 · 2 answers · asked by Anonymous

I am given a torque vs. time graph which starts at (0,0), increases linearly to (4,0.2), then down to (10,-0.1), then back up to (12,0). The question is, a 12-cm-diameter, 4cm-thick, 2.0 kg disk, which is initally at rest, experiences the net torque shown in the graph (described above). What is the disk's angular velocity at t = 12s? Please help!

2007-11-13 11:01:37 · 1 answers · asked by sean77771 1

2007-11-13 10:06:08 · 3 answers · asked by xxbalibluexx 1

This is a physics concept question and I have no clue.

2007-11-13 10:05:45 · 3 answers · asked by JQ 9 2

The axis of the cone is vertical, but it is not very important.

What is minimal distance between the chain and the tip of the cone?

2007-11-13 10:00:49 · 2 answers · asked by Alexander 6

In bungee-jumping, a daring student jumps from a balloon with a specially designed elastic cord attached to his ankles, as shown in Figure P5.69. The unstretched length of the cord is 28.0 m, the student weighs 705 N, and the balloon is 36.0 m above the surface of a river below.

Calculate the required force constant of the cord if the student is to stop safely 3.00 m above the river in N/m

I have no idea what to do. All I know is that I must convert gravitational energy (potential) to either elastic and kinetic energy somehow. Please help. A thorough explanation and reasoning would be greatly apprecitated. Please keep in mind that I am not able to use calculus methods such as integrals and derivitaves, but only transfer of energy.

Thank you. I promise the first person to thoroughly help me will get a best answer.

2007-11-13 10:00:26 · 1 answers · asked by I Need Help 4

i was playing around with some toy magnets and trying to see what all it would stick to and i put it up to the computer sceen and it made the sceen move and it would change colors wherever you moved the magnet...why does it do that and will it mess up the computer?

2007-11-13 09:54:16 · 6 answers · asked by Anonymous

Give an example of a situation that would violate the Law of Conservation of Energy?

2007-11-13 09:48:57 · 1 answers · asked by Anonymous

2007-11-13 09:19:11 · 6 answers · asked by Anonymous

From the two assumptions that Special Relativity makes
1.) The laws of physics are the same in all inertial frames of reference. In other words, there are no privileged inertial frames of reference.
2.)Invariance of c - The speed of light in a vacuum is a universal constant, c, which is independent of the motion of the light source.

make a full theoretical derivation of the Lorentz factor, time dilation, mass and length dilation, and prove that E=m*c^2.

2007-11-13 09:08:54 · 1 answers · asked by Anonymous

A 105kg football player running due north at a speed of 9.5 m/s is tackled by an 80 kg player running in a direction 150 degrees east of north at a speed of 9 m/s. The collision occurs on wet astroturf- so you may ignore friction. In what direction do the entangled players move after the collision? At what speed do they move after the collision?

2007-11-13 09:07:25 · 1 answers · asked by jgill 1

I am probably making this harder then it is but here:

A ball rolls with a constant velocity across a tabletop 0.950m high. It rolls off and hits the ground 0.352m horizontally from the edge of the table. How fast was the ball rolling when it left the table?

I need to know how you arrive at the answer, not just the answer, thanks.

2007-11-13 09:07:21 · 1 answers · asked by sui generis 2

If the WORLD establishes an exact spot and an exact date and time, it does not matter what time but I would assume a date near the current date would make the most sense. This date and time is known world wide and it is the set place and time a person from the future must arrive to prove that time travel into the past was achieved. If said person does not show then we know the entire race was destroyed before we advanced far enough or we did not achieve time travel into the past, ever.

2007-11-13 09:05:31 · 3 answers · asked by Anonymous

Please only answer this if you are positive of the answer. I am in Honors Physics. I need help with my homework dealing with Resonanve and Standing Waves. The first question is exactly this:
The speed of sound is 340 meters per second ^2. If one piece of a cut straw is 0.15 m in length what is the wavelength of the standing wave in the straw when the bottom hole of the straw was NOT covered?

What was the frequency of that wave?

What was the wavelength of the standing wave inside the tube when the bottom hole WAS covered?

Can someone please help me with these 3 problems? From there, I should be fine, but I just need help on the first couple. Thank you.

2007-11-13 08:46:16 · 1 answers · asked by Anonymous

1) explain how hydrogen atoms emit radiation? (2)

2)why do hydrogen atoms emit radiation at specific frequencies? (3)

2007-11-13 08:18:24 · 2 answers · asked by Anonymous

I am 80ft from a wall that is 60ft tall. How fast should I throw a rock if I throw it at 60degrees, and I want it to just clear the height of the wall? Can you show your work too please... thanks alot.

2007-11-13 08:13:39 · 2 answers · asked by zachmebay 2

When you push a 1.81 kg book resting on a tabletop, it takes 2.25 N to start the book sliding. Once it is sliding, however, it takes only 1.51 N to keep the book moving with constant speed.

What is the coefficient of static friction between the book and the tabletop?
What is the coefficient of kinetic friction between the book and the tabletop?

I'm trying to approach this problem by:
f(k)=k*N.
f=kmg
k=f/mg
Wrong approach?

2007-11-13 08:03:01 · 2 answers · asked by revernance 3

Need some help solving these tough Physics questions please....

Question 1
What is the Heat Capacity of a system consisting of a 0.475kg brass cup filled with 0.051kg of water?

Question 2
A container of nitrogen (N2)gas at 9.7oC contains 405 L at a pressure of 3.38 atm. If 27.4 kJ of heat are added to the container, what will be the new temperature?
I think you first determine the numberof moles.

2007-11-13 07:42:23 · 3 answers · asked by Anonymous

One of the examples in my notes states: Dr. D who has a mass of m=68kg easts a 300 Cal candy bar and then climbs 10 stories (Delta h= 35 meters) to his office. How many Calories has he burned?

so Work done = the change of PE (potential energy) = mgh= (68kg)(9.8 m/s^2) (35m) = 23300 J x (1Cal/ 4186 J)= 5.6 Cal

I understand the process of how they get 5.6 Cal but what I don't understand is why they used Word done= the change of PE? I thought Work was = the change of KE (kenetic engery)? isnt potential energy defined as stored energy associated w/position or configuration? or is the potential energy actually stored in Dr. D himself? and KE is derived from a veloctiy acting on a system?? please help explain this!!!

2007-11-13 07:41:35 · 2 answers · asked by Anonymous

2007-11-13 07:39:12 · 2 answers · asked by RogerDodger 1

The combination of an applied force and a
frictional force produces a constant torque of
25 Nm on a wheel rotating about a fixed
axis. The applied force acts for 7.8 s, during
which time the angular speed of the wheel
increases from 0 to 14 rad/s.
a) What is the moment of inertia of the
wheel? Answer in units of kg*m2.
b)The applied force is then removed, and the
wheel comes to rest in 77 s.
What is the frictional torque? Answer in Nm.
c)How many revolutions does the wheel make
during the entire 85 s interval? Answer in
units of rev.

O__o;; I have a midterm soon, and I'd appreciate it if someone could get back to me soon so I can study how to do this right! I don't know if what I have is even the right thing to start with. thanks!

2007-11-13 07:34:29 · 2 answers · asked by Venice Queen 2

Many passages in the Bible refer to God "stretching out the heavens" "like a curtain"
Anyone have any theories or explanations that might offer insight to this? Interesting that 96 percent of the universe is a mystery to us.

2007-11-13 06:31:31 · 3 answers · asked by paul h 7

2007-11-13 05:45:17 · 1 answers · asked by Juniper McClintock 4

2007-11-13 05:35:56 · 3 answers · asked by xannie222x 2

Mercury used to be prepared in the laboratory by heating mercuric oxide

2HgO(s) 2Hg(l) + O2(g)

If 1.87 g of mercuric oxide were heated, what would be the theoretical yield of mercury?

Theoretical yield = ? g Hg

Suppose 1.09 g of mercury was actually collected: what is the percent yield?

Percent yield = %

2007-11-13 05:24:17 · 1 answers · asked by chemgirl78 2

Imagine a train consisting of N frictionless cars following a locomotive that is accelerating the whole train forward with acceleration of magnitude a. Assume that the first car behind the locomotive has mass M. If the tension in the coupling at the rear of each car is 10% smaller than the tension in the coupling in the front of the car, what is the mass of each sucessive car as a fraction of M? What is the total mass of the cars in terms of M? [Hint: You might find it helpful to know that 1+x^2+x^3+...+x^n=(1-x^n+1)/(1-x).]

2007-11-13 05:18:07 · 1 answers · asked by Anonymous