If the velocities of various points in a mechanism are known, then the acceleration of these
points can be easily determined. After knowing acceleration the force, which is the product of
mass and acceleration, can be obtained. From the forces, the stresses (which are equal to force
divided by area) at the various points of the mechanism will be known. These stresses are in
addition to the stresses caused by the working loads. With increasing speeds, higher and higher
accelerations are being called for. Hence the forces and stresses due to higher accelerations are
sometimes more than the stresses caused by the working loads. As acceleration is proportional to
the square of the speed, i.e., acceleration = ω2 × r, hence if the speed of the machines becomes two
times, the centripetal force will become four times. Thus the acceleration diagrams are, therefore,
fundamental to stress analysis of mechanism.