3.41. Pushing on a mass *$ (a) A mass m starts at rest. You push on it with a constant force F. How much time / does it take for the mass to move a distance x? (Both / and x here are measured in the lab frame.) (b) After a very long time, m's speed will approach c. It turns out that it approaches c sufficiently fast so that after a very long time, m will remain (approximately) a constant distance (as measured in the lab frame) behind a photon that was emitted at / = 0 from the starting position of m. What is this distance? (The Taylor series VI + e = 1 + 6/2 will be helpful.)1. Relativistic force. (50 points) Morin exercise 3.41 (p. 158). For part (a), explain your result in the ultrarelativistic limit r - co and the non-relativistic limit a