Homework Help: Galilean relativity problem

1. Sep 17, 2006

busted

2 trains are travelling at constant speeds on 2 parralel straight line. The first A is travelling at 5m/s the second B is travelling at 2 m/s. An observer at the station observes both trains. At a given instant of time, a passenger in A, a passenger in B and the observer at the sation are all aligned along a line normal to the motion of the trains. At that point, a passenger in A drops an ice cube from his drink which he is holding at a height of 1.40m. Using Galilean relativity where will the ice cube land as far as each observer is concerned?

I worked out for A to be x' + u't' = 0 as u' = 0 as there is no horizontal velocity of ice cube relative to A.

Im not sure of the formula to work out B and for ground observer can someone help???

2. Sep 17, 2006

busted

any ideas would be useful, I am not sure whether I am expected to work out the time of how long it will take for the ice cube to land using the distance 1.4 m and gravity???

3. Sep 17, 2006

Daverz

Yes, they expect you to work out the time using gravity and the initial height of the cube, then use Galilean coordinate transformations on this (you could also work out the problems with the cube having an initial velocity equal to the relative velocities, but it sounds like they want you to explicity start with a Galilean transformation, so that you get a feel for how to use Lorentz transformations later on).

Last edited: Sep 17, 2006
4. Sep 17, 2006

busted

any ideas anyone????

5. Sep 17, 2006

busted

is my method for the asnwer for observer A correct??