Inelastic collision of two soccer balls of different masses

In summary: That's because the harder the surface, the more energy is required to bounce the ball back to its original height.
  • #1
GreenSabbath
17
0
You might or might not have seen the astro blaster. But if you drop two soccer balls (stacked together) you'll notice that the smaller top soccer ball lifts up to great heights. I am researching this phenomenon for my extended essay and would really appreciate it if you guys could provide me with some good papers on inelastic collisions. So far I've only been able to incorporate the elastic collison equation along with COR.

http://upload.wikimedia.org/math/5/c/b/5cbdceba601a68315f744dc1c06e9ba7.png" [Broken]


Help and ideas would be really appreciated.
Specially Information about loss from spin etc.

Thanks
Sabbath
 
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  • #2
GreenSabbath said:
You might or might not have seen the astro blaster. But if you drop two soccer balls (stacked together) you'll notice that the smaller top soccer ball lifts up to great heights. I am researching this phenomenon for my extended essay and would really appreciate it if you guys could provide me with some good papers on inelastic collisions. So far I've only been able to incorporate the elastic collison equation along with COR.

http://upload.wikimedia.org/math/5/c/b/5cbdceba601a68315f744dc1c06e9ba7.png" [Broken]


Help and ideas would be really appreciated.
Specially Information about loss from spin etc.

Thanks
Sabbath
I would not concentrate much on the inelastic nature of the collision. The collision is inelastic only for the time that the balls are deformed. At this time, the kinetic energy of the balls is stored as potential energy in the compression of air inside the ball. You have to examine that potential energy and its conversion back into kinetic energy, then analyse the relative timing of the compression/expansion of the two balls in order to explain what happens.

AM
 
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  • #3
The elastic collison equation actually gives me the 9x theoretical velocity amplification I hypothesized, however I've already conducted my experiment ( I increased the mass of my top ball by adding weight making it eventually 5 times heavier than the orignally larger ball). I noticed a decrease in the lift off height, now i need to write about the energy losses incurred and the effect of mass on the rebound height.


Do I make any sense? OR am i just rambling/
Thanks AM for trying
 
  • #4
I guess I have to be a lot more specific to get help. I have two soccer balls and let's say bouncing each of them independently i get two separate coefficient of restitutions for the two balls.
http://upload.wikimedia.org/math/5/c...c1c06e9ba7.png [Broken]
Now in this equation which c is being talked about?
Is it the c of only one of the balls with the floor or is it c1*c2.
Does this equation cover both the energy loss in the collision between the balls and the floor/ or only the balls with each other?
 
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  • #5
The floor's elasticity counts also, so it's c1*c2*c3 (c3 being the floor). Also, the ideal situation, where only the top ball bounces and the bottom ball remains in contact with the floor doesn't always happen. If the bottom ball leaves the floor, then it's using up some of the total kinetic energy after the bounce.

A similar thing can be done on a trampoline. Multiple people land on a trampoline at the same time, then all but one of them quickly raise their legs to pull them off the trampoline, so all the downwards energy from the mulitiple people now goes into catapulting the solo victim skyward.
 
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  • #6
The floor has a value of restitution? sounds very absurd !
Doesnt measuring the rebound height and orignal height of a bouncing ball measure the coefficient of restitution of the ball and floor.
 
  • #7
GreenSabbath said:
The floor has a value of restitution? sounds very absurd ! Doesnt measuring the rebound height and orignal height of a bouncing ball measure the coefficient of restitution of the ball and floor.
Yes, it's really the interaction between ball and floor. Dropping a soccer ball on mud will produce less bounce than dropping it on a solid marble floor.
 

1. What is an inelastic collision?

An inelastic collision is when two objects collide and stick together, resulting in a decrease in their total kinetic energy. This means that some of the kinetic energy is lost and converted into other forms of energy, such as heat or sound.

2. How does the mass of the soccer balls affect the collision?

The mass of the soccer balls affects the collision by determining how much momentum each ball has. The ball with a larger mass will have a greater momentum and therefore will exert a greater force on the smaller ball, causing it to accelerate and move in the direction of the larger ball.

3. What happens to the total kinetic energy of the system in an inelastic collision?

In an inelastic collision, the total kinetic energy of the system decreases. This is because some of the energy is lost during the collision and converted into other forms of energy, such as heat or sound.

4. Can you calculate the final velocity of the two soccer balls after an inelastic collision?

Yes, the final velocity of the two soccer balls can be calculated using the conservation of momentum and the conservation of kinetic energy equations. This will give you the final velocity of the combined mass of the two balls after the collision.

5. How is an inelastic collision different from an elastic collision?

In an elastic collision, the total kinetic energy of the system is conserved, meaning that the objects bounce off each other without any loss of energy. In an inelastic collision, some of the kinetic energy is lost and converted into other forms of energy, resulting in a decrease in the total kinetic energy of the system.

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