- #1
d3nat
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Homework Statement
A football player punts the football so that it will have a time of flight = 4.5s and land 45.7m away. The ball leaves the player's foot 1.52 m above ground.
What is initial velocity? (Magnitude and direction)
Homework Equations
x-x_0 = v_0 * cosθ * t
y-y_0 = v_0 * sinθ * t - 1/2 *g*t^2
v_y = v_0 * sinθ - g*t
v_y^2 = (v_0*sinθ)^2 - 2g(y-y_0)
The Attempt at a Solution
I'm stumped. I can do projectile motion questions, but everytime I have to find initial velocity, I never wind up with the correct answer.
All of the above involve knowing the angle.
I thought maybe θ = tan-1(y/x) but that gives me the wrong angle since that's the angle if the ball was thrown to the ground instead of kicked.
I thought maybe finding the max y height (setting v_y = 0) to solve for angle, but that also involves knowing the angle already.
Help?
Any tips on solving initial velocity questions? I always get stumped on these type. Sigh.