Projectile motion football kick problem

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Homework Help Overview

The problem involves projectile motion, specifically determining the angles of elevation for a football kicker to successfully score a field goal from a certain distance and height. The kicker can impart an initial speed to the ball, and the task is to find the least and greatest angles of elevation for the kick.

Discussion Character

  • Exploratory, Mathematical reasoning, Problem interpretation

Approaches and Questions Raised

  • The original poster attempts to set up equations based on the projectile motion principles but expresses confusion about their effectiveness. They derive a relationship involving time and angles but encounter difficulties in solving it. Another participant suggests an alternative equation for projectile motion and proposes solving for tanθ, which raises questions about the variables used.

Discussion Status

The discussion is ongoing, with participants exploring different approaches to the problem. Some guidance has been offered regarding the formulation of the projectile motion equation, but there is no explicit consensus on the best method to proceed. The original poster continues to seek clarification and assistance.

Contextual Notes

There is some confusion regarding variable notation, specifically the use of 'u' versus 'V0', which may affect the clarity of the discussion. The original poster also indicates uncertainty about their previous attempts and the correctness of their equations.

Cherrybawls
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Homework Statement


A football kicker can give the ball an initial speed of 25 m/s. what are the least and greatest angles of elevation at which he can kick the ball to score a field goal from a point 50m in front of the goalposts whose horizontal bar is 3.44m above the ground?


Homework Equations


I really don't know what to do


The Attempt at a Solution


I figured I could write
V0tcosX=50
and
V0tsinX-.5gt2=3.44

Then I tried to find t in terms of X and got
t=50/(V0cosX)

Then I plugged that into the other equation and I got
50tanX-12250/cos2X-2150=0

I thought then I could find the zeros and that would be my answer but it doesn't seem to be working... I can't figure out why. Maybe I totally missed the answer but either way I still need help lol. Thanks.
 
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you can write the equation of the projectile as
y = x*tanθ - (g/2*u^2)*x^2*sec^2(θ)
Put sec^2(θ) = 1 + tan^2(θ) and solve the quadratic for tanθ.
 
I am confused, what are you referring to with u?
 
Sorry. u is Vo.
 

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