36. Find the velocity of a neutron (rest mass energy 1000 MeV) when its kinetic energy is (a) 100 MeV; (b) 1000 MeV and (c) 10000 MeV. 37. Calculate the amount of work in MeV required to impart an electron (rest mass 0.5 MeV) initially (Ans. (a) 0.42 c; (b) 0.87 c; (c) 0.999 c) at rest, a velocity of (a) :( 3c Find the ratio m/m, in each case. 4 (Ans. (a) 0.076; 1.15 (b) 0.25; 1.51) 38. A neutral pion travelling at a velocity v decays into two photons; one of energy E, travelling in the original direction of the parent pion and the other of energy E, in the opposite direction. If E, = 3E, show that v = c/2.