Why Do Some Objects Bounce While Others Don't?

  • Context: High School 
  • Thread starter Thread starter kashiark
  • Start date Start date
  • Tags Tags
    Bounce
Click For Summary

Discussion Overview

The discussion revolves around the reasons why some objects bounce while others do not, exploring concepts related to momentum transfer, material properties, and the physics of collisions. Participants examine various scenarios involving different types of balls and surfaces, as well as the underlying physical principles such as conservation of momentum and energy, elasticity, and atomic interactions.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants question why a tennis ball bounces off a wall instead of simply transferring its momentum and falling, suggesting that the wall and ball can be thought of as springs.
  • There is mention of conservation laws, with some participants discussing how energy is absorbed and released during collisions.
  • One participant introduces the concept of the coefficient of restitution, explaining how it affects the outcome of a collision, with values ranging from perfectly elastic to perfectly inelastic.
  • Different behaviors of various balls, such as rubber bouncy balls versus tennis balls, are noted, particularly in relation to angular momentum and friction.
  • Some participants highlight the role of material properties in determining the nature of the collision, suggesting that the elasticity of the materials involved influences the bouncing behavior.
  • One participant raises the idea that atomic interactions, including electromagnetic forces, play a role in the bouncing phenomenon, indicating a connection to quantum mechanics.
  • There is a discussion about how the force imparted to the ball affects its elasticity and bounce, with comparisons made between different materials like steel and tennis balls.

Areas of Agreement / Disagreement

Participants express a range of views on the factors influencing bouncing, with no clear consensus on a single explanation. Multiple competing perspectives are presented, particularly regarding the roles of material properties, energy conservation, and atomic interactions.

Contextual Notes

Some assumptions about the ideal conditions for collisions are not fully explored, such as the effects of external forces or the specific definitions of elasticity. The discussion also touches on complex interactions that may not be fully resolved within the scope of the conversation.

kashiark
Messages
210
Reaction score
0
Why do objects bounce? Let's say you throw a tennis ball at a wall. Why doesn't the ball just transfer its momentum to the wall and then fall on the ground? Does the wall receive more momentum than the ball originally had?
 
Physics news on Phys.org
Think about springs.
 
Think about conservation of momentum and conservation of energy. If the ball has some energy that is absorbed by compressing itself against the wall, what must happen next...?
 
oR nEWtons 3'rd law?
 
Think about the following real world situations:

A rubber bouncy ball bouncing on a floor follows an unpredictable path, this is because there is change in angular momentum due to friction with the floor.

A tennis ball follows a more predictable path, except in extreme situations e.g. pro tennis. How does the change in momentum with a top spin on a tennis ball for example compare to the change in momentum for a bouncy ball with top spin on a kitchen floor.

Putty thrown against a wall might not bounce.

A tennisball thrown into a net might not bounce.

Idealistically for direct impact of a sphere onto a fixed plane, v = eu where v is the final velocity, u is the initial velocity and e is the coefficient of restitution, e is 1 for perfectly elastic collisions, e is zero if the two bodies do not separate after collision.

Note: In the real world, it is impossible that the wall remains totally still, you only have to look at skyscrapers swaying in the wind to appreciate that fact.
 
kashiark said:
Why do objects bounce? Let's say you throw a tennis ball at a wall. Why doesn't the ball just transfer its momentum to the wall and then fall on the ground? Does the wall receive more momentum than the ball originally had?
As Cyrus has said, think about the ball AND the wall as springs.

When there is no longer any velocity difference between the wall and the ball, no force acts to encourage further deformation, and the stored potential elastic energy reconverts (partially) into kinetic energy.
 
kashiark said:
Why do objects bounce? Let's say you throw a tennis ball at a wall. Why doesn't the ball just transfer its momentum to the wall and then fall on the ground? Does the wall receive more momentum than the ball originally had?
If a tennis ball bounces off a wall with 100% coefficient of restitution, the momentum transferred to the wall is twice what it would be if the ball just fell to the ground.
 
It really depends on the materials that make up the ball and the wall. Depending on the materials you will get an elastic, inelastic, or somewhere-in-between collision. I don't think this answers your question though. Say the collision is completely elastic so that the ball rebounds completely. The theory behind why it rebounds has to do with electromagnetism and quantum mechanics. The atoms in the ball must repel those in the wall. The degree to which this happens depends on the materials that make up the ball and the wall as stated above. You're asking a rather fundamental and very important question. But to tell you the truth, I don't believe you can answer this question completely, without invoking concepts from quantum mechanics.
 
It depends on how elastic a material is used and how much force is imparted to it. A steel ball is more elastic than he tennis, you may want to use a steel ball in a game that needs to impart as much force to distort it and it exerts an equal restoring force so you get a stunning bounce as well, but this does not mean rigid bodies do not bounce, they just cannot change their configuration
 

Similar threads

High School Why Did My Tennis Serve Bounce Unusually Low?
  • · Replies 15 ·
Replies
15
Views
2K
High School Why Do Objects Bounce? Exploring Momentum and Energy Conservation
  • · Replies 6 ·
Replies
6
Views
2K
High School How to characterize a rubber ball moving horizontally and bouncing off of a vertical wall?
  • · Replies 8 ·
Replies
8
Views
2K
High School Why does energy transfer during collisions?
  • · Replies 8 ·
Replies
8
Views
2K
High School Will a Rigid Ball Bounce off a Wall?
  • · Replies 11 ·
Replies
11
Views
2K
Undergrad Momentum and energy of rebounding balls
  • · Replies 4 ·
Replies
4
Views
3K
High School The physics of flywheel launchers (like tennis ball shooters)
  • · Replies 60 ·
3
Replies
60
Views
7K
Undergrad Why Doesn't the Ball Rotate When Hit by a Pivoting Rod?
  • · Replies 30 ·
2
Replies
30
Views
3K
High School How to shoot longer shots in basketball
  • · Replies 20 ·
Replies
20
Views
3K
High School Questions about momentum and force as well as normal force/friction
  • · Replies 35 ·
2
Replies
35
Views
5K