+73 A pine cone falls from a tree branch that is 144 feet above the ground. After how many seconds does the pine cone land on the ground?
You would use the "Formula for falling bodies" :
d =1/2 x G x t^2, where d = distance fallen, G=Acceleration due to gravity =32.2 ft/s^2, t=time taken.
144 = 1/2 x 32.2 x t^2
144 = 16.1 x t^2 divide both sides by 16.1
8.944 = t^2 take the square root of both sides
t = sqrt(8.944)
t = 2.99 = ~3 seconds - time it takes the pine cone to hit the ground.
