Vertical Projectile Motion: Finding Speed at Maximum Height

[jaded18]

First, let us consider an object launched vertically upward with an initial speed v. Neglect air resistance. What is the speed of the object at the height of (1/2)h max? i know that h max = (initial v in the y direction / 2g) and i also know that Kinitial +Uinitial =Kfinal +Ufinal or 0.5(mv^2) = 0.25(mv^2) + mg(.5 h max)

please help! you will be blessed, i swear... :)

 

[learningphysics]

your formula is wrong.

hmax = (vinitial^2)/(2g)

now use the equation:

vf^2 = vi^2 + 2ad

use d = (1/2)hmax. use a = -g. use vi = vinitial... and that's it. solve for vf.

 

[jaded18]

ok i got it. thanks^^