Ballistic Pendulum Rifle: Solving for Post-Collision Height

In summary, a rifle bullet of mass 0.03 kg traveling at 240 m/s collides with and embeds itself in a pendulum of mass 2.88 kg, initially at rest and suspended vertically by strings of length 2 m. The problem is to determine the height of the pendulum-bullet combination after the collision. The solution involves using the formula for kinetic energy and understanding the concept of energy preservation. The problem is best solved in two stages, the collision itself and the rising of the pendulum after the collision.
  • #1
Tohte
4
0
The problem:

https://tycho-s.phys.washington.edu/cgi/courses/shell/common/showme.pl?courses/phys121/autumn08/homework/06/IE_algebra_ballistic_pendulum_MOM/pic.gif

A rifle bullet of mass m = 0.03 kg traveling at vb = 240 m/s collides with and embeds itself in a pendulum of mass M = 2.88 kg, initially at rest and suspended vertically by massless strings of length L = 2 m.

How high does the pendulum-bullet combination rise after the collision?

I don't know the process for solving this equation, so help would be appreciated.
 
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  • #2
Energy preservation. Kinetic gets converted into potential.
 
  • #3
Okay, so I need to use PE = mgh. I don't understand what I do with the velocity of the bullet and how to setup the problem, if I could get a little more guidance it would help me out

Thanks.
 
  • #4
What is formula for kinetic energy?
 
  • #5
We did this the other day, except we just manipulated the formulas instead of working with actual values.
I am going to attempt to make sense of what I have for that note, so you may hear from me soon...
 
  • #6
Borek said:
What is formula for kinetic energy?

KE = (1/2)mv2
 
  • #7
Is there something you still don't know? Just beware which mass is which - ballistic pendulum mass after hit is that of pendulum PLUS bullet.
 
  • #8
Borek said:
Is there something you still don't know? Just beware which mass is which - ballistic pendulum mass after hit is that of pendulum PLUS bullet.

I don't understand what it is I do with the equation for Kinetic Energy, I'm supposed to find the height of the bullet-pendulum system after the bullet hits the pendulum.
 
  • #9
h as of mgh.
 
  • #10
This problem is best solved in two stages:
(1) The collision itself. You need to find the speed of the block+bullet immediately after the collision. Hint: Energy is not conserved, but something else is.
(2) The rising of the pendulum after the collision. Here you do use energy conservation, as Borek explains.
 
  • #11
Doc Al said:
Hint: Energy is not conserved, but something else is.

Do we have an emoticon for selffishslapping? :blushing:
 

Related to Ballistic Pendulum Rifle: Solving for Post-Collision Height

1. What is a ballistic pendulum rifle?

A ballistic pendulum rifle is a type of firearm that uses a swinging pendulum to determine the velocity of a projectile. It is commonly used in physics experiments to measure the momentum of a bullet or other projectile.

2. How does a ballistic pendulum rifle work?

A ballistic pendulum rifle works by firing a projectile into a suspended pendulum. The projectile embeds itself in the pendulum, causing it to swing to a new height. The change in height of the pendulum can then be used to calculate the velocity of the projectile.

3. What are the benefits of using a ballistic pendulum rifle?

One of the main benefits of using a ballistic pendulum rifle is its accuracy in measuring projectile velocity. It is also a relatively simple and inexpensive method compared to other techniques, making it a popular choice for scientific experiments and demonstrations.

4. Are there any limitations to using a ballistic pendulum rifle?

One limitation of using a ballistic pendulum rifle is that it can only measure the velocity of a single projectile. It also requires a significant amount of space and proper setup to ensure accurate results.

5. How is the data collected from a ballistic pendulum rifle used in scientific research?

The data collected from a ballistic pendulum rifle can be used in a variety of scientific research, including the study of projectile motion, momentum, and energy. It can also be used to test the accuracy and performance of different types of projectiles and firearms.

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