How to Jump Off an 8-story Building

Jumping off an 8-story building is probably not the safest thing to do. For adrenaline junkies this seems like one of the coolest stunts someone could pull off. This man jumped from 129 ft high building into a body of water. Since there are docks in the way of his landing path, calculations need to be made so it is certain he will land in the body of water.

Using kinematic equations, he can figure out where exactly he will land in the water.
 

delta y = -129 ft

Vi = 0

acceleration = 32 ft/seconds squared

Ignoring air resistance, we can solve for time using this kinematic equation

Now that we have time we can plug it into this equation. Since acceleration in the x direction is 0, delta x = velocity times time

This x displacement will give us the distance from the building horizontally.

Since he now knows how far he will go, he will be able to see if he will land in the water or the dock. If this man jumps with a different velocity, his displacement will be thrown off. If it isn't perfect then he will risk landing on one of the docks.

Kinematics is used for any free falls in movies. All television and movie stunts are meticulously calculated before any action is filmed. In Assassin's Creed "Leap of Faith" film, they performed a free fall stunts. In the video game the characters fall from towers into hay baskets and jump from building to building. Although these stunts could be produced digitally, the director of the movie wanted to make sure the stunts look real. Stuntman, Damian Walters, fell from 70 ft, 90 ft, and a remarkable 125 ft. Air bags are used to soften the landing. The air bag must be in the correct spot in order for him to land safely. Physicists can use the kinematic equations to calculate where to place the landing pad for each height of the free fall.

Sources
https://www.wired.com/2016/10/physics-jumping-off-8-story-building-not-dying/

http://www.hindustantimes.com/hollywood/watch-stuntman-s-incredible-125-ft-free-fall-for-assassin-s-creed-film/story-JVeYezfXj43EOkqsP9FLIP.html

http://www.darylscience.com/Demos/StuntMen.html