A projectile is launched from ground level to the top of a cliff which is 195 m away and 135 m high.If the projectile lands on top of the cliff 6.5 s after it is fired, find the initial velocity of the projectile ( (a)magnitude and (b)direction ). Neglect air resistance.

Answer 1

well, what you know
Vertical
hf=ho+vi*t-4.9t^2
135=0+VsinTheta*t-4.9t^2

Horizontal:
195=VcosTheta*t

Ok, t=6.5 so
VcosTheta= 195/6.5

in the vertical equation, solving for VsinTheta=(135+4.9*6.5^2)/6.5

then tanTheta= Vsintheta/VcosTheta, so figure out theta.

then go back knowing theta and figure V.

check my work, I did it in my head.