(25%) Problem 3: A runaway train car that has a mass of 15000 kg travels at a speed of 5.9 ml s down a track. Randomized Variables m = 15000 kg v =5.9rn/s F=1450N E A 50% Part (a) What is the time required for a force F to bring the car to rest, expressed in terms of m, v, and F? D 50% Part (b) Compute this time, in seconds, for a force of 1450 N. (25%) Problem 4: A block of mass m/ = 13 kg slides along a horizontal surface (with friction, uk = 0.39) a distance d = 2.15 m before striking a second block of mass m2 = 7.5 kg. The first block has an initial velocity of v = 7.5 m/s. V m, m, O d Otheexpertta.com 4 50% Part (a) Assuming that block one stops after it collides with block two, what is block two's velocity after impact in m/s? D 4 50% Part (b) How far does block two travel, d2 in meters, before coming to rest after the collision