Step 1 First Draw a Diagram.
Step 2 Identify the givens
g= -9.8 m/sec2
x0 = 0 m
Y-Yo= 80m
V0 = 800m/s -30o inclined from horizontal
Xf= ?
t = ?
Step 3 * A 2 dimensional problem so break it down into x component and y component
Step 4 x component
x= [Vox ][cos 30o][t]
x= [800m/s][cos 30o][tsec]
x=[692.8m/s][tsec] <---------------Need t
Step 5 y component
Y-Yo= Voy - 1/2gt2
80m= -[v][sin30o][t] -1/2gt2
1/2gt2+[v][sin30o][t]+80m=0 <-------Form Quadratic Equation
Solve for t
t= -[v sin 30] +/- [(v sin 30)-(4)(1/2)(9.8)(80)]1/2
(2)(1/2)(9.8)
t= 400+/- 398
9.8
t= 0.2 sec
Step 6 Plug this into initial x component equation
x=[692.8m/s][tsec]
