Two and Three dimensional motion

[KL90]

Homework Statement

A bullet is shot with a speed v0 at an angle θ above the horizontal.
a) what is its maximum height?
b) how long does it take before it hits the earth?
c) where does it strike the earth?

Homework Equations

The Attempt at a Solution

x component: x= x0 + uxt + 1/2axt^2
= v0cosθt

y component: y= y0 + uyt + 1/2ayt^2
= v0sinθt - 5t^2
assume that g=-10

a) when maximizing y, dy/dt=0=v0sinθt - 10t

b) set y = 0 --> 0= v0sinθt - 10t
0 = t(v0sinθ - 10t)
t = 0, t= v0sinθ/10

c) maximize x, I assumed that dx/dt = 0. But I'm not too sure on this part.

 

[rock.freak667]

you have the total time of flight as t=(v₀sinθ)/10. So what the total 'x' distance it travels?