Calculating Vertical Momentum Conservation in a Collision

In summary, the conversation discusses a problem involving momentum conservation in the vertical direction, where a bullet is fired into a block of wood and the height the block will rise is to be determined. The momentum and velocity of the block have been found, but the distance the block travels is still unknown. The hint is given to conserve mechanical energy after the collision. The person is initially confused about the problem, but comes to understand it and asks for help with another problem on the same topic.
  • #1
metalmagik
131
0
Hello, I do not know how to do this momentum conservation problem in the vertical direction, when the object is to find how far the second object went.
A gun is fired vertically into a 1.40-kg block of wood at rest directly above it. If the bullet has a mass of 21.0g (.021 kg) and a speed of 210 m/s, how high will the block rise into the air after the bullet becomes embedded in it?
I have found momentum which was 44.1 kgm/s and the velocity of the block which was 3.15 m/s but I just do not know how I would find the distance the block traveled. The answer is .491 m. Quick help is appreciated, thank you.
 
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  • #2
HINT: After the collision, mechanical energy is conserved.
 
  • #3
I'm still a little confused, I've tried doing mgh = 1/2mv^2 + mgh but I realized I do not have the starting height...I am lost to what else I am supposed to do regarding this problem.
 
  • #4
Just define your coordinate system so that the starting height of the block (i.e. the height of the table, or whatever it's on) is zero. Then when you solve for h that will be the height it reached off the table.
 
  • #5
Thank you, I have solved this problem, it was really just a simple interpretation problem on my part, thanks again, I have one more question I do not quite understand that I expect to see on my exam tomorrow, I will post it in a new thread called "Momentum Particles" if anyone is kind enough to help me with it before the end of tonight.
 

FAQ: Calculating Vertical Momentum Conservation in a Collision

What is momentum conservation?

Momentum conservation is a fundamental principle in physics that states that the total momentum of a closed system remains constant, regardless of any internal changes or external forces acting upon it.

How is momentum conserved?

Momentum is conserved through interactions between objects, such as collisions or explosions. In these interactions, the total momentum of the objects before and after the interaction must be equal. This means that if one object gains momentum, another object must lose an equal amount of momentum.

Why is momentum conservation important?

Momentum conservation is important because it helps us understand and predict the motion of objects in various situations. It is a fundamental law of nature that has many practical applications, such as in engineering, sports, and transportation.

What is an example of momentum conservation in action?

An example of momentum conservation is a game of billiards. When the cue ball hits another ball, the cue ball loses momentum while the other ball gains the same amount of momentum. The total momentum of the system (the two balls) remains constant.

Is momentum always conserved?

Yes, momentum is always conserved as long as there are no external forces acting on the system. In the real world, it is difficult to create a truly closed system, so we may see small changes in momentum due to outside factors. However, in idealized scenarios, momentum is always conserved.

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