一件物件係高處趺落黎

由高處去到低處ge 過程中我地所失去ge 係叫做勢能 (potential energy) . 這是由地心吸力所產生ge (work donw) 公式如下:

W.D.=Fxd=Wxd = mgxh=mgh (weight=W=mg)
W.D=P.E
P.E.= mgh

m=the mass of the object (unit = kg)
g=acceleration due to gravity =9.8 (unit: ms^-2 or Nkg^-1)
h= the displacement of the object (unit : m)

By the conservation of energy ,
Suppose there are no air resistance and other force acts on the object ,
we have:

ΔK.E.+ΔP.E.=0
(1/2)mv^2+mgh=0
=>v^2=-gh
=>v=sqrt(-gh)//

係唔係會比個地下吸晒，定係會係空中有d能量已經冇左

When an object is falling, part of its potential energy will dissipate during the fall because of air resistance.
如果係冇左咁d能量去左邊
The kinetic energy of the object increases during the fall. When it strikes the ground, its energy will transform into heat, which eventually be absorbed by the ground and surrounding air.