A cosmic ray proton is moving at such a speed that it can travel from the moon to earth in 1.70 s. (Assume Earth-moon separation is 3.8 108 m and the speed of light is 3. 108 m/s.)
(a) At what fraction of the speed of light is the proton moving?
(b) What is its kinetic energy?
(c) What value would be measured for its mass by an observer in the Earth reference frame?
(d) What percent error is made in the kinetic energy by using the classical relation?