CENTRE OF MASS System o
The point where whole mass of system is rotatio
supposed to be concentrated.
C.M.
Position of Centre of
mass of system
1. Position of centre of mass depends upon shaped, size
and distribution of mass of body.
r cm =
∑ mi ri Acceleration of Centre
2. Position of centre of mass of an object changes only ∑m i
of mass of system
in translation motion.
acm =
∑ i i
m a
3. Centre of mass & center of gravity coincide for a ∑ mi
small body. Velocity of centre of
4. Centre of mass of rigid bodies is independent of the mass of system
state i.e rest or motion of the body.
V cm =
∑ i i
m v
MOMENT OF
∑ mi
Shape of area Distance x Distance y Inertia of Rotatio
n
I =∑ miri 2
a a
i =1
2 2
where r is distance pe
axis of Rotation.
a Radius of
b
2
2 r12 + r
ANGULAR MOMENTUM K=
r r I
L O = r OA × P (angular momentum about point O) K=
M
The point where whole mass of system is rotatio
supposed to be concentrated.
C.M.
Position of Centre of
mass of system
1. Position of centre of mass depends upon shaped, size
and distribution of mass of body.
r cm =
∑ mi ri Acceleration of Centre
2. Position of centre of mass of an object changes only ∑m i
of mass of system
in translation motion.
acm =
∑ i i
m a
3. Centre of mass & center of gravity coincide for a ∑ mi
small body. Velocity of centre of
4. Centre of mass of rigid bodies is independent of the mass of system
state i.e rest or motion of the body.
V cm =
∑ i i
m v
MOMENT OF
∑ mi
Shape of area Distance x Distance y Inertia of Rotatio
n
I =∑ miri 2
a a
i =1
2 2
where r is distance pe
axis of Rotation.
a Radius of
b
2
2 r12 + r
ANGULAR MOMENTUM K=
r r I
L O = r OA × P (angular momentum about point O) K=
M
