• Support PF! Buy your school textbooks, materials and every day products Here!

The Ballistic Pendulum

  • #1

Homework Statement


Using trigonometry and Fig. 2 in the ballistic pendulum write-up, show that the height h the pendulum rises after capturing the ball is given by: h=R(1-cosθ)

Figure two is here: http://imgur.com/W9nvVZT


Homework Equations



h=R(1-cosθ)

The Attempt at a Solution


So in order for the height to increase I understand that R is the length of the pendulum. θ is the maximum deflection, so since R can't be negative that means cos(θ) must return a negative answer in order for the height to increase. So how do I prove that cos(θ) in this instance will be a negative number, thus making the height increase.
 

Answers and Replies

  • #2
I'm an idiot and figured this question out the second I hit submit, so nevermind I got it! Not sure how to delete a post or if I just let it go!
 
  • #3
arildno
Science Advisor
Homework Helper
Gold Member
Dearly Missed
9,970
132
If you had been an idiot, you wouldn't have found it out by yourself, nor would the best teacher in the world (not me!) been able to make you understand.
So, conclusion:
You are not an idiot after all! :smile:
 

Related Threads on The Ballistic Pendulum

  • Last Post
Replies
5
Views
4K
  • Last Post
Replies
6
Views
2K
  • Last Post
Replies
2
Views
4K
  • Last Post
Replies
9
Views
5K
  • Last Post
Replies
2
Views
2K
  • Last Post
Replies
13
Views
11K
  • Last Post
Replies
1
Views
1K
  • Last Post
Replies
3
Views
5K
  • Last Post
Replies
3
Views
2K
  • Last Post
Replies
1
Views
2K
Top