Question

A shot is fired at 30° with the vertical from
a point on the qruenel with kinetic energy
K. If air resistance is ignored, the kinetic
energy at the top of the trajectory is
1) 3k/4
2)k/2
3) k
4) k/4
​

Answer 1

initially when object is projected at 30 degree with vertical let say its speed is "v"

so the kinetic energy will be

now when object will reach the top position its vertical component of velocity will become zero

It will only have horizontal component of velocity

So at the top position velocity of object will be

now the kinetic energy will be

as we compare this to initial kinetic energy

we can say

so at the top most position its kinetic energy will be one fourth of initial kinetic energy