a golf ball passes on its course exactly over the top of a tree standing 20m high and 40m away from the tee, the ball eventually lands 100m past the tree. what is the original velocity, speed and direction, of the stroke?(adsbygoogle = window.adsbygoogle || []).push({});

this is a question in kinematics and the only force to take into account is gravity,

using

V(t)=Vo+at

X(t)=Xo+Vot+½at²

V²-Vo²=2aΔx

Vx=const=cosθ*Vo

Vy(t)=sinθ*Vo+at

knowing that the ball passed through (40,20) i use the equation for X,

X(t)=40m=cosθ*Vo*t

t=40/cosθ*Vo

Y(t)=20m=sinθ*Vo*(40/cosθ*Vo)-4.9(40/cosθ*Vo)²

=40*tanθ-4.9(40/cosθ*Vo)²

now from here i dont know what to do, one equation with both values i need to find, θ and Vo, have i overlooked something, done something wrong or used the wrong equations for the case?

hope my english and the terms i used are correct, it is a question i have had to translate, thanks

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# Homework Help: Golf ball question, kinematics

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