Page 8 - mechanics

Chapter – 2 Concurrent forces in 2D

2.8 Equilibrium of a Particle

Fig. 2.21 Ring in equilibrium

The term "Equilibrium" indicates a no change in the state of the
particle. This is the case when the effects of the forces applied
to the particle cancel each other. Thus when the resultant of a
system of forces equal zero, the particle is said to be in
equilibrium

R = Fi = 0 (2.39)

i

where Fi are the forces affecting the particle. Indeed, as it is
well known from Newton's second law

Fi = ma (2.40)

i

where m is the mass of body and a is its acceleration, a zero
resultant force on a particle of nonzero mass implies a zero
acceleration. This means no change in velocity. As a special
case a particle at rest having zero velocity will remain at rest.

Solving equilibrium problems is a special case of solving

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