# When an object hits the ground - ?

1. Sep 25, 2006

### the_force

Hi everyone.

I am doing research for a technical analysis study, and I need a little help.

What determines the amount of "bounce" an objects creates when it hits the ground?

Now, this object is a perfect shape hitting a even floor, so the angle should have nothing to do with it.

Is it the speed? weight of object?

What physics/principles are in play?

Thank you for any help.
Take care!
-The Force

Last edited: Sep 25, 2006
2. Sep 25, 2006

### zoobyshoe

I think you're probably not too clear about what the word "buoyancy" means:

http://en.wikipedia.org/wiki/Buoyancy

"In physics, buoyancy is an upward force on an object immersed in a fluid (i.e., a liquid or a gas), enabling it to float or at least to appear lighter. Buoyancy is important for many vehicles such as boats, ships, balloons, and airships."

3. Sep 25, 2006

### the_force

EDIT - Not what I ment to say.

Can you help me out by any chance?
Thanks!

4. Sep 25, 2006

### Danger

I'm not sure if this is the correct term, but the 'modulus of elasticity' of both objects is a primary factor. Every substance has an inherent 'bounciness' based upon its molecular structure. The impact speed and mass of both objects will make a difference as well.

5. Sep 25, 2006

### the_force

Great, thank you for that reply!

Do you know, or know a site that can explain in detail this principle? I need to know this principle and type of physics in great detail, as my research, funny enough, is based on an object hitting the ground :)

Thanks again,
-The force

6. Sep 25, 2006

### zoobyshoe

All this isn't too clear.

Do you want to know what determines how high an object will bounce after being dropped? Or is it thrown onto the floor at an angle?

7. Sep 25, 2006

### the_force

No, just meant that the research I am doing, the out-come can only be a movement up or down.

Sorry for being so vague, but it's kind of hard to explain. Maybe if I explain the research a little more.

Let's say you are charting something that is seemingly random, but with some predictability, you have a support for the graph and a resistance. Now, when you add volume into why the object is falling, will it cause a larger (higher bounce) when whatever you are charting hits the support line.

I need to know the principle behind why an object bounces back up when it hits a surface, and the reason for how high it goes.

Thank you all!
-The Force

8. Sep 25, 2006

### Danger

I don't want to sound rude, but you'll really have to explain that in a lot more detail. Some of the terms that you use don't seem to make sense in the context in which you're using them. I'm sure that it's just a matter of you knowing what you want to say and expressing it in a way that's clear to you. To the rest of us, though, who have no clue what the initial conditions are, it's pretty vague.

9. Sep 25, 2006

### the_force

Ok, I can understand that. Let me try again.

When a ball hits the ground and bounces up, what principle is being used? What are the physics involved?

10. Sep 25, 2006

### Andrew Mason

The bounce depends on the ability of the object to convert its kinetic energy into potential 'spring' energy. It also depends on the hardness of the ground.

The amount of energy it can regain after stopping depends on the amount of potential elastic energy stored in the object when it is stopped (maximum compression). This requires a very high spring constant.

If the ground deforms on impact, energy will be lost, so maximizing bounce requires a very hard surface.

AM

11. Aug 22, 2010

### holohedron

12. Aug 22, 2010

### Staff: Mentor

Four year old thread. Locked.

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