There are two types of equilibrium: static and dynamic. Static equilibrium occurs when a body is at rest, such as a book lying on a table. Dynamic equilibrium occurs when a body is moving with a constant velocity, such as a car moving at a steady speed. Dynamic equilibrium can be translational, where the body moves with constant acceleration in the x or y direction, or rotational, where the body rotates with constant angular velocity like the Earth rotating around the Sun. For a body to be in equilibrium, the sum of all forces and sum of all torques acting on it must equal zero.

1. PRESENTED BY:
MUHAMMAD FAHEEM UD DIN
KHAN.
EQUILIBRIUM AND
ITS TYPES

2. EQUILIBRIUM
•State of body in which it is moving with
constant velocity or in static. Under the action
of many forces.
•We can say that if acceleration is zero(a=0)
than body is in equilibrium.
Now we will discuss its types:
There are two types of equilibrium
i. Static
ii. Dynamic
Static equilibrium:
“a body is said to be in static equilibrium if it
is at rest means it is stable in at a

3. EXAMPLE:
A book is lying on a table etc.
DYNAMIC EQUILIBRIUM:
It is defined as:
“when a body is moving with costant velocity
then we can say that is in dynamic equilibrium”
EXAMPLE:
A car moving with uniform velocity under the
action of many forces.
The dynamic equilibrium is further divided
into two types:
•Translational equilibrium.
•Angular equilibrium.

4. Translational equilibrium:
a body is said to be in translational if it is
moving in (x,y) direction with constant acceleration.
V= constant.
a=0.
Rotational equilibrium:
if a body is moving with constant
angular velocity then it is rotational equilibrium.
e.g. rotation of earth around the sun in 24 hours.

5. CONDITIONS FOR EQUILIBRIUM:
Following are the two conditions of
equilibrium on following which we can say
that a body is in equilibrium:
• the sum of all forces are equal to zero
∑ Fx=0 ; ∑ Fy=0 ; ∑F=0
• the sum of all torque or moment of forces
is equal to zero.
∑ torque=0 ; ∑ M=0