DLC Blog

World Jump Day

I read an interesting article the other day and I thought I would share with you.

Have you heard of the World Jump Day?

It states that if millions and millions of people jump at same time, it will stop the global warming because it will shift the earth from its orbit a bit, or whatnot.

Well, this is a bad joke.

Let’s look at this in terms of physics.

Let’s assume the average mass of 6 billion human on earth is 70kg (154lb).
The acceleration due to gravity is 9.81kg/s^2 (32.17ft/s^2).
Also assume the average height of a vertical jump is 0.6m (2 ft).

From this data, we can find how much work is generated when everyone jumps and lands at same time.
First, find how fast they will be when they land:

vf^2 = vi^2 + 2*g*x
vf^2 = 0^2 + 2*9.81*0.6
vf = 3.41m/s

vf = velocity when everyone lands
vi = velocity at the peak of jump (0).
g = gravity
x = height of the jump

Next find the energy created when everyone lands:
KE = 1/2*m*v^2
KE = 1/2*(70*6E9)*3.41^2
KE = 2.44E12 J

KE = kinetic energy
m = mass of everyone combined
v = velocity when everyone lands

So 2.44E12 Joules of energy will be generated when everyone on the earth jumps and lands at same time. How much energy is 2.44E12 Joules? It’s equivalent to 6506 tons (1.43E7lb) of TNT (dynamite) or 1/3 of the energy created by a hydrogen bomb.

The hydrogen bombs have been tested on the surface of the earth and nothing has changed, thus everyone on the earth jumping and landing at same time doesn’t do anything.

Miyagi

Posted by Hayato at November 13, 2006 04:28 PM in Science.