Work done by a Gravitational
Force
W
g
= mg d cos
Φ
Δ
K = W
net
K
f
– K
i
=
0 = W
g
+ W
a
W
a
= - W
g
= mgd cos
Φ
where
Φ
is angle between F
a
and
the displacement d
W
up
=
-mgd
(going up)
W
down
=
mgd
(going down)
