Nope! The severity index is 3018, well over the deadly 1000 mark. So it’s curtains for Bruce Willis. In order for Bruce to remain conscious, he would have to come to a halt over a period of 1.8 seconds.
Okay, so how did they do it in the film? The stunt designers have to slow the body’s momentum gradually, to lessen the shear strain. Remember our formula?
The more gradual the change in momentum the weaker the forces acting on the body. For long falls of over 100 feet, they use elastic decelerators, like a bungee cord.
In a bungee jump, the key is the elasticity in the cord.
Although the jumper reaches the end of the cord (L), it continues to stretch (l) until he reaches its full extremity. 
Thus the total length of the cord is L+l and the energy has been converted to the elastic potential energy of the cord, acting as a brake. Since energy is conserved in the jump, the gravitational potential energy of the jumper must equal the elastic potential energy of the cord. 
|
