The Physics of Skydiving: Heavier falls faster!

From the beginning we are taught the classical physics lesson that objects of different mass fall at the same rate towards the ground, a classical example of free-fall. Remember that free-fall does not consider air resistance or any other drag force which actually exist in the real world.

If we take an example of a skydiver, we would learn that a heavy skydiver would fall faster than a lighter one. Lets see what forces are actually acting on the skydiver when he jumps from the plane.

The Gravity

As soon as the sky-diver jump out of the plane the acceleration due to gravity pulls him down at 9.8m/s2.

Skydiving

Drag Force

Editor's Note: Thanks to reddit user /u/Bozmancc for the correction. The text is updated with the correction. Previous text: The drag force, caused by the air resistance, opposes the pull due to gravity and decreases the acceleration.

The drag force, caused by the air resistance, creates an acceleration in the opposite direction to the acceleration due to gravity and this continues until the net acceleration is zero.

Skydiving Drag force

Terminal Velocity

Editor's Note: Thanks to reddit user /u/Bozmancc for the correction. The text is updated with the correction. Previous text: When the drag force decreases the acceleration due to gravity to almost zero, at that time the diver is moving at zero acceleration or terminal velocity.

When the drag force cancels the acceleration due to gravity and the net acceleration decreases to zero, at that time the diver is moving at zero acceleration or terminal velocity. Average terminal velocity is 193kmph (120 mph) in a face-down and arms stretched position. The velocity can be increased by diving head first and arms and legs flattered which results in a faster fall at 322 kmph (200 mph).

Sky diving Terminal Velocity

Heavier skydivers will fall faster

The heavier the skydiver's body the faster it will fall toward the ground due to greater terminal velocity. This is evident from the equation of terminal velocity.

Terminal Velocity

Parachute to the rescue

Falling at the rate of 193 kmph (120 mph) is still pretty fast so in order to land safely we need to increase the drag force by pulling out the parachute. The parachute decreases the terminal velocity to a safe 20 mph by increasing the drag force with its large surface area.

Sky diving parachute

The world record for the highest jump was done by Felix Baumgartner from 127,851 ft (23.3 miles), in a mission to the edge of the space on 14th October 2012. He reached a maximum velocity of 1357.64 kmph (843.6 mph), breaking the sound barrier (which is 760 mph), before he started to slow down due to denser atmosphere and increasing drag force.

15406   09/08/2014

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