(adsbygoogle = window.adsbygoogle || []).push({}); 1. A boy can throw a stone at 14 m/s. At what angle must he throw it in order to hit a window which is 10m away horizontally and 5m above the ground?

2. I would assume we have to use trig ratios and the kinematics equations.

v = u + a.t

v^2 = u^2 + 2.a.s

s = u.t + 1/2.a.t^2

3. Diagram:

(see attachment or http://img377.imageshack.us/my.php?image=imgwn9.png )

I know that time is a constant for both the horizontal and vertical components, so I presume that it would not affect the equations.

My info:

-Vertical motion

(t=0)

s = 5m

u = 14 m/s sin.(theta)

a = +9.8 m/s^2

-Horizontal motion

(t=0)

s = 10m

u = 14 m/s cos.(theta)

a= 0

So how do I find theta? Am I missing any equations? Is my diagram correct? Isu = 14 m/s sin.(theta)andu = 14 m/s cos.(theta)correct? Thanks :)

I'm thinking of using some equation in theta... but what those equations are is beyond me =[

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# Homework Help: Projectile Motion

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