🚀 go-pugleaf

In article <2pi4st$9gv@cwis.isu.edu>, rudeeric@cwis.isu.edu (Eric Rude) writes:
|>
|>
|> Hello.
|> the physics students at Pocatello High School asked me to post these five
|> questions in hope that someone might have some answers:
|> 1. If light is a particle, how can it travel at the speed of light
|> without becoming an infinite mass?

   Photons, the particles of light have no REST mass (meaning if you bring
a photon to rest (zero velocity) it can't exist).  Any particle without a rest mass
travels at the spped of light.   Particles with rest mass can never reach
the speed of light because then they will have infinite mass

|> 2. If light is a particle, when it leaves a flashlight why doesn't it
|> have enough momentum to push the flashlight backward?

The momentum of a photon is related to its energy not mass times velocity
since its mass is zero.  The energy flux from your flashlight is several
orders of magnitude too low for their to be any appreciable momentum flux
from the photons.  Note as an aside, in the very early universe, the transfer
of momentum from high energy photons of mass particles (protons) was
an important process.

|> 3. relativity states that to the observer, the mover's time always goes
|> slower. Then how can one person's clock be ahead of the other's,
|> considering that either one could be considered the mover or the observer?

You have to tie the clocks to an external frame of reference in order to
make a sensible measurement.  Two observers by themsleves can never
determine who is moving and who is at rest.

|> 4. If you could stand in a black hole and shine a light straight up,
|> would the light escape, turn around and come straight back down, or orbit
|> to the right or left?

See previous post on description Black Holes - you can't stand in one.

|> 5. If we could travel at speeds greater than the speed of light, could we
|> travel back in time?
|>

Well we can't travel faster than light so anything that follows is just
conjecture and can never be proven either through experiment or theory.
This is a question like, what's inside a black hole or what's beyond the horizon
of the universe.  The answers to such questions require faster than light
travel.

|> Thanks in advance!
|>
|> --
|> Eric Rude	Pocatello High School
|> 325 N. Arthur, Pocatello, ID 83204-3101
|> rudeeric@cwis.isu.edu
|> (208)-233-2056