Equilibrium of a particle:
A particle is said to be in equilibrium if it remains at
Or has constant velocity if originally in motion most
How ever the term of "equilibrium" or more specifically
"static equilibrium" is used to describe the things at
It is necessary to satisfy Newton's first law of motion.
∑F = 0
Where F is a vector.
If the particle lays on X-Y plane.
The each forces can be solved into I & J for equilibrium.
F1 cos θ – F2 cos φ = 0
F1 sin θ + F2 sin φ = 0
Equilibrium of rigid body:
We can develop the both necessary and sufficient
condition for equilibrium.
This body is subjected to force, couple and moment
This is the resultant of gravitational force, electric,
magnetic or contact forces caused by adjacent
The internal forces caused by inter action between
particles can't be seen in figure and equal but
So, we cancel it.
F: is the force exerted by the spring
K: is spring constant
: the length of spring after elongation
: the original length before elongation
. The force exerted by spring
. Free body diagram
It is a successful application of equation
of equilibrium require complete specificant
of all known and unknown external force
that acts on the body , the best way for this
to draw the free body diagram.
It is necessary to draw all forces and couple
Example(1): In the shown figure. Determine the tensions in 3
The equations of equilibrium: