A stone is released from rest from the top of a tower high
PHYSICS · Multi-part · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
A stone S1 is released from rest from the top of a tower 78.4m high. Exactly two seconds later, another stone S2 is projected vertically upward from the foot of the tower with a speed of 39.2ms−1. Air resistance is negligible.
(i) Calculate the time elapsed after the projection of S2 when the two stones cross each other.
(ii) Determine the height above the ground at which the crossing occurs.
(iii) Find the relative speed of the two stones at the instant they cross.