posted by promice .
a stone is thrown vertically upwards fron the edge of a cliff of height 100m, with a velocity of 9m/s. The stone then fall to the ground(the foot of the cluff). Determine the total time the stone will take to hit the ground
V = Vo + g*t.
Tr = (V-Vo)/g = (0-9)/-9.8 = 0.918 s.
Tf1 = Tr = 0.918 s. = Fall time from hmax to edge of cliff.
h = Vo*t + 0.5g*t^2 = 100m.
9*t + 4.9t^2 = 100
4.9t^2 + 9t - 100 = 0.
Use Quad. Formula.
Tf2 = 3.69 s. = Fall time from edge of cliff to Gnd.
T = Tr + Tf1 + Tf2.
T = 0.918 + 0.918 + 3.69 = 5.53 = Total
time in flight.