Grade 12 Physics problem -- A small bungee cord powered catapult

In summary, Patrik's problem statement lacks information about the problem, and he has not posted an attempt to solve it. He has posted an image of his handwritten notes, which violate forum rules. He needs to follow the prompt given to him in Post #7, and first find the amount of potential energy stored in the elastic bungee cord.
  • #1
PatrikL
5
0
Homework Statement
I am really stuck on this problem and need help. Please see pictures.
Relevant Equations
Please see picture
20210408_181444.jpg
20210408_181510.jpg
 
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  • #2
Welcome to PhysicsForums, Patrik.

It looks like you left some information out of your "Problem Statement" above. Could you please post the whole problem statement? The problem does not seem to have enough information to me.

Also, please post your work to start trying to figure out the solution. What you have posted as an image above seems more like some more details about the problem.

Thank you. :smile:
 
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  • #3
Hi.
That is all the information our teacher gave us...
 
  • #4
PatrikL said:
Hi.
That is all the information our teacher gave us...
That's very doubtful. What is the difference between the problem statement image that you posted and the image of your handwriting? Why did you need to post the additional image of your handwritten notes if the problem statement was complete?

The main issue I have is there is no information in the problem statement that has anything to do with friction or elastic energy losses...
 
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  • #5
Welcome, Patrik! :cool:
Did you get the numbers that you have shown from a diagram?
 
  • #6
Lnewqban said:
Welcome, Patrik! :cool:
Did you get the numbers that you have shown from a diagram?
Yes they did
 
  • #7
PatrikL said:
Yes they did
So the information in your handwritten image is just part of the problem statement, and you have not posted any attempt. That violates forum rules.
It may still be helpful to see the diagram. It could contain information you have overlooked.

The first step is to find how much energy was stored in the stretched elastic. Please attempt that.
 
  • #8
Hi here is my attempt. Not sure if it is correct but I'm trying .
 

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  • #9
PatrikL said:
Hi here is my attempt. Not sure if it is correct but I'm trying .
You need to follow the prompt given to you in Post #7. First, find the amount of potential energy stored in the elastic bungee cord. (Note that in your Step 6 you have assumed it to be zero!)
 
  • #10
Hi. I used the above suggestions and arrived at this ..see picture
 

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  • #11
In Step 1 you are finding the initial speed. This was not the suggestion. The suggestion was to find the initial elastic potential energy. That should be Step 1.

By the way what makes you think the acceleration is a constant 9.8?
 
  • #12
PatrikL said:
Hi. I used the above suggestions and arrived at this ..see picture
If you had read the forum rules you would also know that images are for printed matter and diagrams. Your handwritten posts are too hard to read. Please take the trouble to type in your working. LaTeX is preferred, but you can also use the "..." pulldown above the typing area for subscript and superscript and button for special characters.
Also, I strongly recommend working entirely symbolically until the final step. Resist plugging in numbers straight away. Create variable names for the given numbers. This has many advantages.
 

FAQ: Grade 12 Physics problem -- A small bungee cord powered catapult

What is a bungee cord powered catapult?

A bungee cord powered catapult is a device that uses the elastic potential energy of a stretched bungee cord to launch an object. It works by pulling back the bungee cord and releasing it, which causes the bungee cord to snap back and propel the object forward.

How does a bungee cord powered catapult work?

A bungee cord powered catapult works by converting the potential energy stored in the stretched bungee cord into kinetic energy. When the bungee cord is released, the potential energy is released and the bungee cord snaps back, transferring the energy to the object being launched.

What factors affect the distance and velocity of the object launched by a bungee cord powered catapult?

The distance and velocity of the object launched by a bungee cord powered catapult are affected by the elasticity and length of the bungee cord, the mass of the object being launched, and the angle at which the bungee cord is released.

How can you calculate the potential energy and kinetic energy of a bungee cord powered catapult?

The potential energy of a bungee cord powered catapult can be calculated using the equation PE = 1/2kx^2, where k is the spring constant of the bungee cord and x is the distance the bungee cord is stretched. The kinetic energy can be calculated using the equation KE = 1/2mv^2, where m is the mass of the object being launched and v is the velocity of the object.

What are some real-world applications of a bungee cord powered catapult?

Bungee cord powered catapults have many real-world applications, such as launching projectiles in military and defense systems, propelling aircraft from aircraft carriers, and launching objects in amusement park rides. They can also be used in science experiments to study the principles of potential and kinetic energy.

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