Does velocity from rotational Ek add to a total velocity of a body?

  • Thread starter rammer
  • Start date
  • #1
23
0
If we have a ball rolling down from inclined roof that has bottom part at certain height about the ground. I want to know where does the ball land after it leaves the roof. So at this point potential energy is transfered to kinetic (rotational + translational).

My question is: What is the expression I derive an initial velocity from? Is it EK(transl) or EK(transl)+EK(rot)?

I think it should be only EK(transl), because I'm interested only in motion of a centre of mass, right?
BUT, exercises in my book always counts with EK(rot), so I'm pretty confused.

Can you please make it little more clear to me??
 

Answers and Replies

  • #2
Doc Al
Mentor
45,259
1,615
To find the final velocity of the ball as it leaves the roof you must use conservation of energy. That includes all forms of mechanical energy, which in this case is both rotational and translational KE.

Even though all you care about is the translational speed of the ball, in order to correctly find that speed you must use conservation of energy properly.
 
  • #3
23
0
thank you
 

Related Threads on Does velocity from rotational Ek add to a total velocity of a body?

Replies
11
Views
8K
Replies
4
Views
937
Replies
3
Views
901
Replies
1
Views
1K
Replies
15
Views
4K
  • Last Post
Replies
1
Views
1K
Replies
4
Views
2K
  • Last Post
Replies
1
Views
10K
  • Last Post
Replies
4
Views
7K
  • Last Post
Replies
14
Views
2K
Top