# 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 [itex]\theta[/itex] = 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 [itex]\phi[/itex] = 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= X_{o} + V_{ox}t

Y= Y_{o} + V_{oy}t – (1/2)at^{2}

**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 V_{ox} = 69.5cos(65) and that V_{oy} = 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 = V _{o} + (1/2)at^{2}* as a hint for this. Isn’t this wrong though, seeing as how the velocity should be multiplied with time?

http://ift.tt/1bKRvfW

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