Lets say there is a long space bus, travelling just 30m/s less than the speed of light and Im in space in an inertial frame of reference and observing this bus. Then, a girl from the end of the bus starts running to go to the front with a speed of 50m/s. So, with respect to me, will she travel faster than c? If not, why? And with respect to girl, how will the surroundings look like(I mean the people sitting around her, the surroundings outside the window). And with respect to the other people in the bus and me, what will the motion of the girl be like? Pls enlighten me!!
No. c is the only absolute constant in the universe.
No. speed addition of velocities close to c s = (u + v) / [ 1 + (vu/c2) ] So, you are on a spaceship (a big one) that is observed to travel at 0.75 c. You can fire space torpedo that also travels at 0.75c RELATIVE to the ship. What speed does a motionless observer say the torpedo goes? s = (0.75c + 0.75c) / [ 1 + (0.75*0.75) ] = 0.96c