24 Theory of Machines
2. Newton's Laws of Motion.
3. Mass and Weight.
6. Absolute and Gravitational
Units of Force.
7. Moment of a Force.
9. Centripetal and Centrifugal
10. Mass Moment of Inertia.
11. Angular Momentum or
Moment of Momentum.
16. Principle of Conservation of
17. Impulse and Impulsive Force.
18. Principle of Conservation of
19. Energy Lost by Friction
Clutch During Engagement.
20. Torque Required to
Accelerate a Geared System.
21. Collision of Two Bodies.
22. Collision of Inelastic Bodies.
23. Collision of Elastic Bodies.
24. Loss of Kinetic Energy
During Elastic Impact.
In the previous chapter we have discussed the
kinematics of motion, i.e. the motion without considering
the forces causing the motion. Here we shall discuss the
kinetics of motion, i.e. the motion which takes into
consideration the forces or other factors, e.g. mass or weight
of the bodies. The force and motion is governed by the three
laws of motion.
3.2. Newton's Laws of Motion
Newton has formulated three laws of motion, which
are the basic postulates or assumptions on which the whole
system of kinetics is based. Like other scientific laws, these
are also justified as the results, so obtained, agree with the
actual observations. These three laws of motion are as
1. Newton's First Law of Motion. It states, "Every
body continues in its state of rest or of uniform motion in
a straight line, unless acted upon by some external force."
This is also known as Law of Inertia.
The inertia is that property of a matter, by virtue of
which a body cannot move of itself, nor change the motion
imparted to it.
Chapter 3 : Kinetics of Motion 25
2. Newton's Second Law of Motion. It states,
"The rate of change of momentum is directly
proportional to the impressed force and takes place in
the same direction in which the force acts."
3. Newton's Third Law of Motion