Help with this 9th grade motion problem

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Homework Help Overview

The discussion revolves around a 9th grade physics problem involving two stones thrown vertically upwards with initial velocities U1 and U2. The task is to prove that the heights reached by the stones are in the ratio of U1 squared to U2 squared.

Discussion Character

  • Exploratory, Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants discuss the relationship between initial velocities and heights, with one participant questioning their understanding of the relevant equations. Others suggest using conservation of energy to find the height relationship, while some express uncertainty about the formulas being used.

Discussion Status

The discussion is ongoing, with participants exploring different approaches and clarifying concepts. There is no explicit consensus yet, but some guidance has been offered regarding the use of conservation of energy and the need for appropriate formulas for height under constant acceleration.

Contextual Notes

One participant notes that they have not yet learned about the law of conservation of energy, which may affect their ability to engage with some suggestions. Additionally, there is a mention of confusion regarding the correct formula for height in the context of constant acceleration.

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Help with this 9th grade "motion" problem

Homework Statement



2 stones are thrown vertically upwards with initial velocities U1 & U2. Prove that heights recahed by them is in ration U1squared:U2squared.

Homework Equations



S=u+at u being initial velocity

The Attempt at a Solution



since a and t will cancel out, ration should be u1: u2 not the squared. What am I missing?
 
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Use the conservation of energy to find the relationship between the 2 heights.
 


Care to explain it a bit more? Which is the equation you are referring to?

We are yet to learn law of conservation of energy.
 


If you throw a stone up with velocity U1, how high does it get?
 


johsun123 said:

Homework Statement



2 stones are thrown vertically upwards with initial velocities U1 & U2. Prove that heights recahed by them is in ration U1squared:U2squared.

Homework Equations



S=u+at u being initial velocity
This is incorrect. u+ at is the formula for the speed at t seconds given initial velocity u and acceleration t. Do you have a formula for distance or height of an object moving with constant acceleration?

The Attempt at a Solution



since a and t will cancel out, ration should be u1: u2 not the squared. What am I missing?
 

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