Problema Solution
If an object is thrown upward with an initial velocity of 64 ft/sec, its height after t sec is given by h=64t-16t^2. Find the number of seconds the object is in the air before it hits the ground.
Answer provided by our tutors
The total displacement is 0 as it reaches the ground.
so 0 = 64 - 16t^2
=> 64 = 16 x t^2
=> t^2 = 64 / 16
=>t^2 = 4
=> t = root(4) = 2