# 2D Kinematics Problem involving subtended angle

1. The problem statement, all variables and given/known data

Mortar crew is near the top of a steep hill. They have a mortar. They angle this mortar at an angle of $\theta$ = 65° . The crew fires a shell at a muzzle velocity of 228 ft/sec (69.5 m/s). How far down the hill does the shell strike if the hill subtends an angle of $\phi$ = 32° from the horizontal?

How long will the mortar remain in the air?
How fast will the shell be traveling when it hits the ground?

Relevant diagram: http://ift.tt/1m5d84y
2. Relevant equations

Kinematic Equations:

X= Xo + Voxt

Y= Yo + Voyt – (1/2)at2

3. The attempt at a solution

First off, I’m not expecting to get all of my questions answered. I just need a little push.

I’m not sure where to start off at here. The fact that there are two angles here confuses me in regards to how they work in the equations.

I can say that Vox = 69.5cos(65) and that Voy = 69.5sin(65).

I’m really thrown off by the way the angles work here, and whether the distance works with a simple range equation. Any tips on where to start?

edit: Additionally, I was given the equation d = Vo + (1/2)at2 as a hint for this. Isn’t this wrong though, seeing as how the velocity should be multiplied with time?

http://ift.tt/1bKRvfW