kike paul

I tried all the formulas i know but i cannot answer it I really need your help in this question.. A projectile was launched 64° above the horizontal, attaining a height of 10 m. What is the projectile's initial speed?

Given: Vi = 12 m/s a = - 2.5 m/s2 t = 5s Required: Vf (final velocity) Solution: a=Vf^2 - Vi^2 / t -2.5 m/s = Vf^2 - (12m/s)^2 / 5s -2.5 m/s = Vf^2 - 144m^2/s^2 -2.5m/s over -144 m^2/s^2 = Vf^2 0.13 m/s = Vf

thanks