Physics Kinetic Energy Question

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Homework Help Overview

The discussion revolves around a physics problem involving the comparison of the heights reached by two identical cannonballs shot straight up with different initial velocities. The subject area is kinetic energy and its relationship with potential energy in the context of projectile motion.

Discussion Character

  • Exploratory, Conceptual clarification, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the conservation of energy, noting the transition from kinetic to potential energy as the cannonballs ascend. There are questions about the appropriate formulas to use and whether kinetic energy is necessary for solving the problem. Some suggest using kinematics equations instead.

Discussion Status

The discussion is active, with participants exploring different approaches to the problem. Some guidance has been offered regarding the use of kinematics equations, but there is no explicit consensus on the best method to proceed.

Contextual Notes

Participants express a need for clarification on concepts and equations, indicating that they are working within the constraints of homework rules that discourage direct solutions.

Ion1776
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You are about shoot two identical cannonballs straight up into the air. The first cannonball has 2.0 times as much initial velocity as the second. How many times higher will the first cannonball go compared to the second?

How do you do this
 
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Total energy = Kinetic + Potential in this scenario, right? Also note that the energy is conserved (well, assuming no air resistance)

As each ball travels higher into the air the potential becomes larger, which means the kinetic energy decreases until all the energy is potential. This is where each ball will stop.

Does this help?
 
So what formula should I used, how should i plug the numbers in
 
I actually don't think you need kinetic energy for this... Try using kinematics equations.
 
How about helping me out, and showing me how to do this.

I know my equations, I don't know what to use, plus I need to understand the concept...
 
Well, since they're both shot straight up, the only acceleration you need to worry about is gravity. Find an equation with only initial and final velocity, acceleration, and displacement. Set the equations equal to each other. Solve for final position.

Sorry, there's really not too much more I can say without giving you the work, and the point is just to point you in the right direction.
 

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