Collisions problem (How should I approach it)

In summary, the conversation discusses a problem on collisions and the use of conservation of linear momentum and energy to solve it. The problem involves 3 unknowns and the participants discuss the equations and variables needed to solve it.
  • #1
Hindi
9
0
Hi all,

I came across a problem on collisions on one of my professors old exams. The problem is:

http://home.comcast.net/~msharma15/problem_2.jpg

The way I am trying to approach it is by applying the conservation of linear momentum and energy, but the problem is that I still get left with 3 unknowns.

Here is what I know:
Before the collision, only block A has kinetic energy.

After the collision, the K.E. of system is (1/2 K.E. initial). block A has -1/2MV^2 and block B has 1/2MV^2.

The final collision is what confuses me. Should I just work with K.E.i (only block A moving) with conservation of linear momentum?

Any help would be greatly appreciated. Thanks!
 
Last edited by a moderator:
Physics news on Phys.org
  • #2
by cons of p,
[tex]m_1v_{1i}=m_1v_{1f}-m_2v_{2f}[/tex]
where v_2f is reckoned as negative
By the energy conditions,
[tex]m_1v_{1i}^2=\frac {1}{2}(m_1v_{1f}^2+m_2v_{2f}^2)[/tex]
which gives two equations with two unknowns.
 
  • #3
Thanks for the reply
StephenPrivitera. I am just wondering why you made m_2v_2f negative in the first equation?? Should it be the other way around?
 
  • #4
The equations should be:
[tex]m_1v_{1i}=-m_1v_{1f}+m_2v_{2f}[/tex]
[tex]\frac {1}{4}m_1v_{1i}^2=\frac {1}{2}(m_1v_{1f}^2+m_2v_{2f}^2)[/tex]
(where the speeds are all positive)
 

1. What is a collision problem?

A collision problem is a type of physics problem that involves two or more objects that are moving and may come into contact with each other. The goal is to determine the outcome of the collision, such as the final velocities of the objects.

2. How should I approach a collision problem?

The first step in approaching a collision problem is to identify the type of collision, such as elastic or inelastic. Then, use the conservation of momentum and/or energy equations to solve for the unknown variables.

3. What information do I need to solve a collision problem?

To solve a collision problem, you will need the masses, initial velocities, and the type of collision of the objects involved. You may also need other information, such as coefficients of restitution or friction.

4. What are the key concepts to understand when solving a collision problem?

The key concepts to understand when solving a collision problem are conservation of momentum and conservation of energy. It is also important to understand the difference between elastic and inelastic collisions and how to use equations and variables to solve for unknowns.

5. How can I check my answer for a collision problem?

You can check your answer for a collision problem by using the conservation equations and plugging in your calculated values to see if they satisfy the equations. You can also use the laws of physics, such as the law of conservation of energy, to see if your final answer makes sense.

Similar threads

  • Introductory Physics Homework Help
Replies
12
Views
1K
  • Introductory Physics Homework Help
Replies
6
Views
889
  • Introductory Physics Homework Help
Replies
10
Views
1K
  • Introductory Physics Homework Help
Replies
8
Views
3K
  • Introductory Physics Homework Help
Replies
20
Views
879
  • Introductory Physics Homework Help
Replies
4
Views
363
  • Introductory Physics Homework Help
Replies
4
Views
1K
  • Introductory Physics Homework Help
Replies
10
Views
1K
  • Introductory Physics Homework Help
Replies
15
Views
1K
  • Introductory Physics Homework Help
Replies
4
Views
742
Back
Top