In this question use g=9.8g = 9.8g=9.8 m s−2^{-2}−2
A tower stands on horizontal ground. The top of the tower is 40 metres above the ground.
A stone A A\,A is released from rest at the top of the tower.
At the same instant, a stone B B\,B is projected vertically upwards from the foot of the tower with speed 20 m s−1^{-1}−1.
Both stones move freely under gravity in the same vertical line.
Show that the two stones are at the same height 2 seconds after they start to move.
Find the height above the ground at which the two stones are at the same height.
State one modelling assumption you have made.