- #1
Alex13
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Homework Statement
A rifle, in which the initial velocity of the bullet is 460m/s, is aimed at a small target 800 metres away at the same height as the rifle. At what angle above the ground must the rifle be pointed so that it hits the target?
**
x = horizontal distance
t = time
Vx = horizontal velocity
g = gravitational acceleration
y = vertical distance
Vyi = initial vertical velocity
Vyf = final vertical velocity
**
so far I know:
x is 800m (given)
g = -9.81m/s2, since the bullet is being pulled down by gravity
y = 0, because the bullet does not travel any vertical distance because it lands at the same height that it is shot at.
http://img144.imageshack.us/img144/1736/physicsproblem2bs1.jpg
Homework Equations
vertical:
y = Vyit + .5gt2
y = Vyft - .5gt2
g = (Vyf - Vyi)/t
Vyf2 = Vyi2 + 2gy
horizontal:
Vx = xt
The Attempt at a Solution
I'm almost clueless on how to approach this one. I can't even see how there is enough info given to be able to solve it. all I have so far is a diagram
http://img464.imageshack.us/img464/4261/physicsproblemvf7.jpg
Thanks in advance!
Alex
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