posted by Claudia .
A certain freely falling object requires 1.25 s to travel the last 35.5 m before it hits the ground. From what height above the ground did it fall?
Let T be the time required to fall the entire height H. You will have to solve for both.
H = (g/2) T^2 = 4.9 T^2
H - 35.5 = (g/2)*(T-1.25)^2
= 4.9*(T-1.25)^2 = 4.9T^2 -12.25T + 7.656
Subtract the second equation from the first and solve for T. Then use that T to solve for H.
35.5 = 12.25T -7.7
T = 3.53 s
H = 60.9 m
Do it yourself and check my numbers; there could be a mistake.