1. The problem statement, all variables and given/known data A lift starts from rest and travels with constant acceleration 4 m/s^2.It then travels with uniform speed and comes to rest with constant retardation of 4 m/s^" The total distance traveled is d and the total time taken is t. Show that the time spent travelling at a constant speed is (t^2 - d)^(1/2) 2. Relevant equations I called the maximum velocity "v", the time spent accelerating "t1", the time spent at constant speed "t2" and the time spent decelerating "t3" distance traveled when accelerating "d1",when at constant velocity "d2" and when decelerating "d3" 3. The attempt at a solution I used v = u + at, to find that t1 = v/4 and t3 = v/4. I then multiplied the times by (1/2)v to get the distances in both cases d1 = v^2/8 and d3 = v^2/8. I then said d2 = vt2 =d - (v^2)/4 I divided v by both sides to get t2= (d/v-(v/4). I made t1 + t2 + t3 = t and simplified to get (4d + v^2) / (4v) = t. I tried to isolate v but couldn't since there was a v squared. My main problem here I think is I cant get v on its own so i can't get rid of v in t2. Any help would be appreciated.