Projectile Motion, Vector Component Confusion

[cire792]

Homework Statement

Canon fired at 45Degrees, at 300m/s
Assuming no air resistance,
a= -9.8m/s^2
ViX = 300cos45 = 212m/s
ViY = 300sin45 - 212m/s
Displacement = 2293m [used vf^2=vi^2+2a(d)] rearranged for d, and vf=0, at highest peak.

Time the ball is in the air= ?

Homework Equations

Thinking I have to use this, but this is where my math skills are rusty.

dy = vi (t) + 1/2 a(t)^2

The Attempt at a Solution

time = -1038

 

[Delphi51]

You noted that Vy = 0 at half time.
So you can use Vy = Viy + at to find the half time. Viy = 212