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???