Kinematics of a kicked football

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Homework Help Overview

The discussion revolves around a kinematics problem involving the trajectory of a kicked football. Participants are exploring the equations of motion relevant to projectile motion, particularly focusing on horizontal and vertical positions as functions of time.

Discussion Character

  • Exploratory, Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants discuss the necessity of both horizontal and vertical motion equations, with some suggesting that the vertical position equation is crucial for solving the problem. There are attempts to identify where the original poster may be going wrong in their approach.

Discussion Status

The discussion is ongoing, with participants providing hints and questioning assumptions. Some guidance has been offered regarding the need for vertical motion equations and consideration of significant figures, but no consensus or resolution has been reached.

Contextual Notes

There is mention of specific values and equations that the original poster has attempted to use, as well as a note on the importance of significant figures in the context of the problem.

Josh0768
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Homework Statement
Please help, I am thoroughly stumped trying to solve this kinematics question on my study guide. I’ve tried everything I know of but cannot get an answer that’s even an option.
Relevant Equations
R = v^2sin(2theta)/g
v^2 = vi^2 -2gd
x = vcos(theta)t
CE4D7DFC-357D-4EE6-8509-0FA17B8B104A.jpeg
 
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Josh0768 said:
x = vcos(theta)t
You could solve that equation for the time it takes to reach the horizontal position of the goal post.
It seems to me that you have forgotten to write down the equation for the vertical position of a ballistic object as a function of time.
 
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Josh0768 said:
I’ve tried everything I know
I assume you would like us to tell you where you are going wrong. Just a moment while I get out my crystal ball...
 
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Hello Josh.

How are you going to solve this problem without the equation for vertical position as a function of time? If you can figure out the elapsed time when the football is at the required height (3.05 m.) I think you can you then solve the rest of the problem.

AM
 
Josh0768 said:
Homework Statement: Please help, I am thoroughly stumped trying to solve this kinematics question on my study guide. I’ve tried everything I know of but cannot get an answer that’s even an option.
Homework Equations: R = v^2sin(2theta)/g
v^2 = vi^2 -2gd
x = vcos(theta)t

View attachment 249715
according to me the answer should be "G". Use equation of trajectory and put x=32.3 v=22.2 and theta=49.4 after plugging in the values you should get some "y" after that just subtract the height of the goal post.
 
If significant figures are to be taken into account, none of the answers are correct.

AM
 

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