PDA

View Full Version : Various questions


desigonzalez
Dec 3, 2004, 09:58 PM
1- if you watch a clock on a train that goes past you at a constant speed v, how do you see it turnning?

2- which of the following forces it is possible to shield against?
a- electromagnetism
b-gravity
c-a and b
d-just magnetism
e-just the electrostatic force

3- the earth has dust raining on it all the time from space, coming in pretty much equally from all directions. What do you think should happen to the rate at which it turns based down and then speed up?

4- most of planets going around the sun go around in the same plane. They stay in that plane to conserve what?

urmod4u
Dec 5, 2004, 03:56 PM
1) and 2) Electromagnetism can be shielded. Gravity cannot be shielded.
Magnetic and electrostatic forces are different expressions of the same fundamental physical force, i.e. electromagnetism. As said before, it can be shielded.
(we know of 4 fundamental physical forces: gravity, electromagnetism, strong nuclear force and weak nuclear force).
3) if dust falls in equally from all directions (ALL directions, referenced to very distant galaxies), no rotation speed change of the earth will occur because all brought in impulse together will avarage to zero.
4) Conservation of the 'impulse momemtum'.