Rotating Object - zero KE

  • Thread starter esmeralda4
  • Start date
  • #1
52
0

Main Question or Discussion Point

Hi,

Since velocity is a vector quantity I assume it follows that KE must also by a vector since KE=1/2mv squared.

Is it true to say a rotating object has zero total velocity since + = - and therefore the total KE is zero?

Thanks
 

Answers and Replies

  • #2
jtbell
Mentor
15,518
3,353
No, because kinetic energy is not a vector quantity. It is a scalar. Think of the ##v^2## as coming from the vector dot product of the velocity with itself: ##v^2 = \vec v \cdot \vec v = v_x^2 + v_y^2 + v_z^2##.

There is such a thing as rotational kinetic energy.

http://hyperphysics.phy-astr.gsu.edu/hbase/rke.html
 
Last edited:

Related Threads on Rotating Object - zero KE

  • Last Post
Replies
5
Views
3K
  • Last Post
Replies
2
Views
2K
  • Last Post
Replies
5
Views
2K
  • Last Post
Replies
22
Views
5K
Replies
3
Views
2K
Replies
14
Views
2K
Replies
16
Views
15K
  • Last Post
Replies
1
Views
1K
  • Last Post
Replies
3
Views
2K
Top