Two parallel elevators at rest are 175 meters apart. The two will approach each other from their initial positions. The upper elevator has a constant downward acceleration of 0.5 m/s^2 and the lower elevator has an upward constant acceleration of 1.5 m/s^2. If the lower elevator starts 4 seconds after the upper elevator, determine:
a) the total time of travel for the lower elevator
b) the total distance traveled by the lower elevator
c) the velocity of the lower elevator when passing the upper elevator