1. A ball (B) of mass m moves with velocity v relative to an observer (O). The momentum of B relative to O is p=mv according to Newtonian mechanics and p=gamma x mv according to Special Relativity. What do the above two theories predict for B's momentum if its speed equals c, the speed of light?
2. Alice travels from Earth to a distant star that is 25 light years away. One light year is the distance that light propagates in one year. Bob stays at home on Earth. Alice moves at v=0.9998c relative to Bob. The gamma factor is 50. How far has Alice traveled according to (i) her measurements and (ii) those of Bob?