Angular Velocity: Find Launch Angles for Projectile

[trigunesq]

Homework Statement

A projectile is launched at 36 m/s and travels 100 m horizontally. If it is to be able to just barely clear a 10 m wall, between what two angles should the projectile be launched with respect to the horizontal?

Homework Equations

vf=vo+at
x=volt+1/2at^2
vf^2=Vo^2+2ax

 

[tiny-tim]

Welcome to PF!

Hi trigunesq! Welcome to PF!

(have a theta: θ and try using the X² and X₂ tags just above the Reply box )

They're asking you for the two angles from which it will be 10m up when it's 100m along.

Call the launch angle θ, and the time taken t, then use your constant acceleration equations for the x and y directions separately (a = 0 for the direction, of course), to get a pair of equations from which you can eliminate t to get a quadratic equation for θ (with two solutions! ).

What do you get? ​