Work, Power and Energy Part 1

Let u be the velocity with which the particle is thrown and m be the mass of the particle. Then
KE=‌

1

2

mu2 .....(1)
At the highest point the velocity is u‌cos‌60∘ (only the horizontal component remains, the vertical component being zero at the top-most point).
Therefore kinetic energy at the highest point,
(KE)H=‌

1

2

mu2cos260∘

=‌

K

4

[From eq (1)]