3. WHAT IS CENTER OF GRAVITY?
The center of gravity of an object is the
point at which we can consider the
weight of an object to be concentrated.
4. WHAT IS CENTER OF GRAVITY?
The center of gravity of a collection of masses is the point
where all the weight of the object can be considered to be
concentrated. If (xcg,ycg) are the coordinates of the centre of
gravity of a collection of point masses m1 , m2 , etc, located at
coordinates ( x1,y1 ), ( x2,y2 ), respectively, then
5. DIFFERENCE BETWEEN CENTRE OF MASS AND
CENTRE OF GRAVITY
It is common to assume the centre of mass
and the centre of gravity to be the same,
but this is not the case.
6. Determining the Centre of Gravity for
Symmetrical Bodies
For simple shaped object, the centre of gravity
can be determined by the following way:
When we balance an object with the help of a
string or an edge, the point at which the object
balances is the centre of gravity.
8. An object is in equilibrium in a reference
coordinate system when all external forces
acting on it are balanced. This means that the
net result of all the external forces and
moment acting on this object is zero.
The state of a body at rest or in uniform
motion, the resultant of all forces on which is
zero.
10. THERE ARE THREE (3) CONDITIONS
FOR EQUILIBRIUM
1) STATIC
2) DYNAMICS
3) NEUTRAL
11. STATIC EQUILIBRIUM
There are two (2) conditions for an object
be in Static Equilibrium
1) The first condition of equilibrium states that for
object to remain in equilibrium, the net force
acting upon it in all directions must be zero.
2) The second condition of equilibrium states that
net torque acting on the object must be zero.
12. STATIC EQUILIBRIUM
An object at rest is described by
First Law of Motion. An object in static
equilibrium has zero net force acting
it.
13. DYNAMIC
EQUILIBRIUM
No acceleration means that all of the
forces must be balanced and there isn't
any net force available to accelerate the
object. It is just like static equilibrium
except that the object is moving at a
constant velocity.
14. NEUTRAL EQUILIBRIUM
When the center of gravity of a
body lies at the point of
suspension or support, the body
is said to be in neutral
equilibrium.
Example: rolling ball
Editor's Notes
This is the center point from which the weight is evenly dispersed on all sides. We can use the center of gravity to determine exactly when an object will reach its tipping point and fall over.
The centre of mass is a point at which mass distribution is equal in all directions, and it doesn’t depend upon the gravitational field. The centre of gravity is a point in an object where the distribution of weight is equal in all directions, and it does depend on the gravitational field.
However, an object’s centre of mass and centre of gravity lies at the same point in a uniform gravitational field.
Situational example: A BOOK KEPT ON A TABLE AT REST. A CAR MOVING WITH A CONSTANT VELOCITY, CHEMICAL REACTION WHERE THE RATES OF FORWARD REACTION AND BACKWARD REACTION ARE THE SAME.
The word equilibrium implies balance. In particular, static equilibrium suggests that a system is stable and at rest. However, to be completely balanced, the net torque must also be zero.
The above statement simply means that the body must not be experiencing acceleration. In the form of an equation, the first condition of equilibrium is denoted as follows:
Fnet = 0
A body satisfies the second condition for equilibrium when the resultant torque acting on it is zero. Mathematically it is represented as: ∑ τ = 0
We may say that an object at rest is in equilibrium or in static equilibrium.
The examples of static equilibrium are: (i) a book resting on a table (ii) a car parked on a road (iii) a boy standing still on the podium (iv) a ball kept on the ground. Hence, any non-moving stationary object can be considered to be in static equilibrium.
REMEMBER: In static equilibrium, the velocity and acceleration is ZERO.
IF IN STATIC EQUILIBRIUM, THE VELOCITY AND ACCELERATION IS ZERO, HERE IN DYNAMIC THE (velocity is not zero, but acceleration is zero)
When you observe a car in motion, you will notice that it moves with a constant velocity on a straight road.
This means that the car has no net external force acting on it. In other words, this equilibrium is classified as dynamic equilibrium.
If a ball is pushed slightly to roll, it will neither come back to its original nor it will roll forward rather it will remain at rest.
If the ball is rolled, its center of gravity is neither raised nor lowered. This means that its center of gravity is at the same height as before.
