An object is released from rest at an unknown height h above the ground. One second

later a second object is released from rest at the same height. When the first object strikes
the ground, the second is 20 m above the ground. What is the initial height h?

1 answer

If the first object takes t seconds to hit,

h - 4.9t^2 = 0
t = √(h/4.9)

the second object is thus

h-4.9(t-1)^2 = 20
h = 31.63 m