Ballistic pendelum problem

  • Thread starter Oomair
  • Start date
  • #1
Oomair
36
0
[SOLVED] Ballistic pendelum problem

Homework Statement


16 g rifle bullet traveling 180 m/s buries itself in a 4.0 kg pendulum hanging on a 3.5 m long string, which makes the pendulum swing upward in an arc. Determine the horizontal component of the pendulum's maximum displacement


Homework Equations


arc length s= rtheta


The Attempt at a Solution



i don't think the block and bullet make a angle with a vertical
so work= F*s where S= Rtheta, but i can't find theta,
 

Answers and Replies

  • #2
tiny-tim
Science Advisor
Homework Helper
25,838
255
Hi Oomair! :smile:

Energy isn't conserved in the collision (you know that because the question tells you that the bullet "buries itself" in the pendulum).

So use conservation of momentum to find the initial speed of the pendulum.

Then find its maximum height by … ? :smile:
 
  • #3
Oomair
36
0
ok i found the max height which came out to be .0262 meters, but its wants the horizontal displacement, i don't know how to relate the height to the horizontal displacement,

since its displacement is like an arc, so S= rtheta, so this is where I am stuck, i have tried freebody diagrams and even used integration,
 
  • #4
tiny-tim
Science Advisor
Homework Helper
25,838
255
Hi Oomair! :smile:

Yes, .0262m looks right.

ok, the rest is just geometry.

Horizontal displacement just means the sideways component of distance.

So draw a triangle. The hypotenuse is 3.5. One side is 3.5 minus .0262. So the third side is … ? :smile:
 
  • #5
Oomair
36
0
thanks, that worked, i didnt know that the hypotenuse could be the length of the string, what a weird problem lol
 

Suggested for: Ballistic pendelum problem

  • Last Post
Replies
3
Views
255
  • Last Post
2
Replies
50
Views
656
  • Last Post
Replies
29
Views
234
  • Last Post
Replies
6
Views
277
  • Last Post
Replies
15
Views
195
Replies
3
Views
477
  • Last Post
Replies
2
Views
340
  • Last Post
Replies
22
Views
485
  • Last Post
Replies
4
Views
326
Top