Question

A parachutist flying in an aeroplane jumps when it is at height of 3 Km above ground. He opens his parachute when he is about 1 km above ground. Describe his motion.

Answer 1

suppose the aeroplane is flying horizontally. Now parachutist is like a freely falling body in vertically downward direction and has uniform velocity equal to aeroplane velocity in horizontal direction till he opens parachute at a height 1km from the ground.

now after opening parachute , air resistance and buoyancy force also acts on him along with gravitational force. in the presence of these forces , net acceleration of parachutist becomes zero after falling through certain height . now he attains constant velocity known as terminal velocity and finally he reaches the ground with the same terminal.

Answer 2

Initally the path is a parabola as seen by an observer on the ground. It is a vertical straight line as seen by the pilot. He opens his parachute, it is moving vertically downwards with decreasing velocity and finally it reaches the ground.