Center of Mass - WordPress.com
Download
Report
Transcript Center of Mass - WordPress.com
IHSAN DOĞRAMACI FOUNDATION
BILKENT ERZURUM LABORATORY HIGH SCHOOL
CENTER OF MASS
LOGO
Cemre Çise KADIOĞLU 102
KEY WORDS
Center of gravity, plumb line
Weight, torque
Resultant-gravitional forces
Stability
Balance
Equilibrium
Turning effect
What is centre of mass?
Gravitional forces on
particles of stick
The small forces act like a single force at
G. This means that they have the
resultant force at G.
The resultant force is the stick’s weight.
G is the centre of mass.
What is centre of mass?
Centre of mass of a body is the body that
moves as though all of the mass were
applied there.
Finding centre of mass
If the object is uniform, for example a meter
stick, the center of mass will be at the exact
geometric center.
G
Intersection pointCentre of mass
But, if the shape is irregular we use plumb line.
Draw lines from each vertex along the plumb
line by assuming that the point is on that line
After drawing the lines the centre of the mass
will be on the intersection point of these lines.
Finding the centre of mass
But, if the shape is irregular we use plumb line.
Draw lines from each vertex along the plumb
line by assuming that the point is on that line
After drawing the lines the centre of the mass
will be on the intersection point of these lines.
Plumb line
Intersection point-centre
of mass
Balancing unequal masses are again
about centre of mass
M2
For example,
M1
d2
d1
The bus is heavier than the car so they’re
not in balance.
In order to balance the system, we
should change their distances to the
support.
d1
m1.d1=m2.d2
Now they’re in balance.
d2
Stability –Equilibrium
If an object isn’t moving and remainig
same, the object is stable.
State of rest or balance due to the equal
action of opposing forces is called
equilibrium.
When the object is stable it’s also in
equilibrium which means the forces
acting on the object and the forces
turning effects are in balance.
Stability-Equilibrium
Will turn to
its original
position
Small
force will
turn it over
Will definetely fall
over before another
force is applied
Types of equilibrium
There are three states of equilibrium,
Stable equilbrium
The objects that have wide base also
have the lower centre of mass.
The lower the centre of mass is, the
more stable object is.
So it’s more difficult to fall over an object
with wider base.
Unstable equilibrium
The objects that have very little base,
have high centre of mass.
And if these objects are tilted the centre
of mass immediately passes beyond the
base.
So they’re not stable and it’s easy to fall
these objects over.
Neutral equilibrium
The objects that are in neutral
equilibrium stay where they’re lefted.
When moved, it changes the position.
Wherever they stay, their center of mass
is always over their base.
References
Complete Physics for IGCSE
http://dev.physicslab.org/Document.asp
x?doctype=3&filename=RotaryMotion_Ce
nterMass.xml
http://dictionary.reference.com/browse/
equilibrium
http://en.wikipedia.org/wiki/Center_of_
mass
http://eteach.engr.wisc.edu/meibom/esp
p/slides/espp.ppt
http://solar.njit.edu/~cdenker/physics11
1_lecture08.ppt