Question

solved a ball is dropped from the top of a tower 100 meter high. simultaneously another ball is thrown upwards from ground with a speed of 50 m/s . after what time do they cross each other.

Answer 1

h1 = -1/2 g t^2 + 100

h2 = -1/2 g t^2 + 50 t

the balls cross when h1 equals h2

looks like 2 sec

Answer 2

question cant be solved untill its is clear whether its a free falling case or not.