# Falling off of a building and ANY equations that would be associated with that

1. Jan 3, 2010

### Meprathe

I was just wondering about any equations that would play a part in this situation. Obviously gravity plays a role but like calculating the force you'd hit the ground at like the force in pounds or something anything really is what I need it's just a general question. Preferably a 4 story building (17meters tall)

2. Jan 3, 2010

### diazona

Hmmm... *checks book* gee, sorry, we're all out of equations for 4 story buildings. Can you work with 5 stories? :rofl:

It sounds like you have a specific question in mind, even though you're trying to sound like you don't. Is this some sort of homework problem? If so, it should be asked in the homework forum... and whether it is or not, you'll get better information if you make your question as specific and detailed as possible. What exactly do you want to know?

3. Jan 3, 2010

### Meprathe

Well I guess I want to know is how would I calculate the amount of force you hit the ground with? Or something similar to that

4. Jan 3, 2010

### Staff: Mentor

There is no single force when you hit the ground. f=ma, but the impact is short so the acceleration is large but inconsistent (ie, if your feet hit the ground first, your legs might decelerate very fast while your body is still decelerating slowly).

5. Jan 4, 2010

kinetic energy= 1/2 mv^2
impact = FT
acceleration= v-u/t
velocity = d/t
etc..

6. Jan 5, 2010

### Lsos

As russ waters said, it's going to be hard to figure this out. You can figure out how fast you're going right before you hit the ground, and we know you won't be moving after...but it's how fast you go from moving to not moving is the hard part, and is directly related to how much force you hit the ground with.

Is it concrete, is it ground, is it snow, is it a pillow. If it's concrete, how do you hit it? If you hit it with your head, initially the skull will provide a large force, since it's hard. Once the skull cracks and the brain starts to get smashed, the force decreases. The jawbone will in turn increase the force again....

The point is different materials bend/ deflect/ break differently, and different people will bend/ deflect/ break differently. To complicate this further, the way they hit each other will change the way they bend/ deflect/ break.

So basically, if you want to figure this out, testing is unfortunately the only way.