Inelastic collisions

  • Thread starter Misr
  • Start date
  • #1
385
0

Main Question or Discussion Point

hi,
Look at this experiment
http://img243.imageshack.us/img243/4150/inelasticcollision2.jpg [Broken]

http://img13.imageshack.us/img13/2914/inelastic2.jpg [Broken]

in this experiment , the law of conservation of energy can't be applied because the KE is lost
but this is not true for all the cases of inelastic collision.
for example
when the ball hits the ground , we hear a sound and if the ball rebounded it doesn't reach the same height because KE is converted into sound energy but not lost so law of conservation of energy can be applied although its inelastic collision.

so why the book wrote that "in elastic collision the law of conservation of energy can't be applied"
although this doesn't work at all cases (i think so)
 
Last edited by a moderator:

Answers and Replies

  • #2
648
2
It's just a case of careless wording in the book.
It should say that conservation of mechanical (in this case k.e. and p.e.) energy cannot be applied. The broader application of conservation of energy, where you include other forms such as sound, always applies.
In many books, when dealing with mechanics problems like this one, "energy" is taken to mean mechanical energy.
 
  • #3
385
0
Yes , thank you
 

Related Threads for: Inelastic collisions

  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
1
Views
1K
  • Last Post
Replies
4
Views
591
  • Last Post
Replies
5
Views
2K
  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
11
Views
979
  • Last Post
Replies
14
Views
963
  • Last Post
Replies
0
Views
604
Top