tolong yaa gimana caranya..

diketahui :
m = 4 kg
v2 = 10 m/s -> (h2 = 6 m)
g = 10m/s^2
ditanya : h1 (h sblm kelapa jatuh)..?

penyelesaian:
Em1 = Em2
Ep1 + Ek1 = Ep2 + Ek2
(m . g . h1) + (1/2 . m . v1^2) = (m . g . h2) + (1/2 . m . v2^2)
(4 . 10 . h1) + (1/2 . m . 0^2) = (4 . 10 . 6) + (1/2 . 4 . 10^2)
*kecepatan awal sblm kelapa jatuh = 0
40.h1 + 0 = 240 + 200
40.h1 = 440
h1 = 440/40
h1 = 11 m