Question

Rock A is thrown straight up with an initial speed of 6m/s from the top of a building 52m tall. At the same moment, rock B is thrown straight up from the ground with an initial speed of 25m/s.A) How high above the ground are the rocks when they pass each other? B) If rock B is thrown 2s after rock A, where do they meet?

Answer 1

Rock A
ha = 52 + 6 t - 4.9 t^2
Rock B
hb = 0 + 25 t - 4.9 t^2
so
52 + 6 t = 25 t
52 = 19 t
====================
ha = 52 + 6 t - 4.9 t^2
hb = 0 + 25 (t-2) - 4.9 (t-2)^2 = -4.9 t^2 + 44.6 t - 69.6
equal when
52 + 6 t - 4.9 t^2 = -4.9 t^2 + 44.6 t - 69.6
38.6 t = 121.6