(a) How long will a stone take to fall to the ground from the top of a building 80 m high and (b) what will be the velocity of the stone on reaching the ground ? (Take g = 10 m s^-2 )

A body falls from the top of a building and reaches the ground 2.5 s later. How high is the building ? (Take g = 9.8 m s^-2)

A stone is dropped freely from the top of a tower and it reaches the ground in 4 s. Taking g = 10 m s^-2, calculate the height of the tower.

A pebble is dropped freely in a well from it's top. It takes 20 s for the pebble to reach the water surface in the well. Taking g = 10 m s^-2 and speed of sound = 330 m s^-1, find: (i) the depth of water surface, and (ii) the time when echo is heard after the pebble is dropped.