Question

Potential energy of a projectile at maximum height is 3 by 4 times kinetic energy of projection its angle of

Answer 1

mv²/2×3/4=mv²cos²x/2
3/4=cos²x
√3/2=cosx
x=30°

Answer 2

The formula for Kinetic Energy is 1/2mv^2.

m = Mass of the object

v = Net velocity of the object

A projectile at maximum height has no vertical velocity component(Vy), so it only has a horizontal velocity component(Vx). So your net velocity would be what your horizontal component would be.


Notice how the net velocity(red line) at the highest height is completely horizontal, that is because there is no vertical component.

So you take your mass and multiply that by the net velocity squared and divide what you get by 2.

You have your Kinetic Energy!