Momentum and kinetic energy

  • #1
528
33
"if kinetic energy of system of particles is zero, then linear momentum of that system of particles is zero but the reverse is not true. That is if linear momentum of a system of particles is zero, then the kinetic energy may not be zero"

This is what I got from my text. Can you provide me with some examples because I am a bit confused. Can you provide some explanation?
Is this true for angular momentum?
 

Answers and Replies

  • #2
Vanadium 50
Staff Emeritus
Science Advisor
Education Advisor
2021 Award
28,060
12,604
Consider two particles with mass m, one with velocity +v and one with velocity -v.
 
  • Like
Likes AdityaDev
  • #3
528
33
Consider two particles with mass m, one with velocity +v and one with velocity -v.
So momentum is zero and kinetic E is not zero. Can you give an example for kinetic energy zero and momentum non zero?
 
  • #4
82
4
So momentum is zero and kinetic E is not zero. Can you give an example for kinetic energy zero and momentum non zero?
KE = sum of 1/2 mv2. Can any of those terms be negative?
Or, imagine covering the whole system with a curtain or box and treating it as one object of total mass M and velocity V.
P=MV, while KE= 1/2MV2+ KE(within system, relative to the center of mass)
If KE = 0, what does that imply? Assume masses are never negative.
 
  • Like
Likes AdityaDev
  • #5
528
33

Related Threads on Momentum and kinetic energy

  • Last Post
Replies
3
Views
1K
  • Last Post
Replies
17
Views
3K
  • Last Post
Replies
3
Views
2K
  • Last Post
Replies
5
Views
2K
  • Last Post
Replies
7
Views
3K
  • Last Post
Replies
4
Views
1K
  • Last Post
Replies
13
Views
28K
  • Last Post
Replies
2
Views
2K
  • Last Post
Replies
8
Views
2K
  • Last Post
Replies
29
Views
7K
Top