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## Homework Statement

A gun is located at the origin. The gun is aimed 36.87 degrees above the horizontal. A vertical wall is located at x = 18m. The flat and level floor is at y=0m. Ignore air friction.

a) What is the minimum initial speed necessary for the bullet to reach the wall without hitting the floor?

b) Suppose the initial speed is 15 m/s. Does the bullet first hit the floor or the Wall? Where does it hit? (I can do this part, just thought I'd throw it in for some reason.)

c) What initial speed is required in order to hit the wall 3.00m above the floor?

## Homework Equations

d=vt

Vf^2 = Vo^2 +ad

d = Vot + 1/2at^2

## The Attempt at a Solution

a)

I'm really having troubles with this.

I don't know the initial or final velocity or time. I thought that since that since the bullet will hit the wall at the same height that it was fired from, then half way along (x=9m) the bullet would peak, so I could use that point knowing the Final velocity in the y would be 0... then I could solve for the initial velocity in the Y, then use trig to find the initial velocity.

Vfy^2 = Voy^2 + 2ad

then: d = v*(2)t

but unfortunately I don't know what the displacement (in the y) would be at this point.

I'm pretty sure I need to find the initial velocity in the Y, and then time before I can do anything else, but I'm totally stuck.

I might be on the complete wrong track

b)

I can do this, it's for fun if you want.. hah yeah right?

c)

this is basically the same as a) i think...

Please help, my final is tomorrow and this is the only type of projection question I can't figure out.