Laws of Motion- Notes
Kinetics is the study of the displacement, velocity and acceleration of a body in motion along with the forces responsible for the motion.
A force applied by an external agency either accelerates or retards a body.
The tendency of a body moving with uniform velocity in a straight line to stay in motion with the same uniform velocity, when the net external force is zero, is called inertia.
Inertia also means resistance to change or resistance to acceleration.
Newton’s First Law of Motion
Newton’s First law of Motion states: ‘’Every object continues to be in its state of rest or of uniform motion in a straight line unless compelled by some external force to act otherwise.’’
If the net external force on a body is zero, it acceleration is zero and vice-versa.
A body accelerates only when a net external force acts on it.
Newton’s Second Law of Motion
Momentum of a body is defined as the product of its mass, m, and velocity, v, and is denoted by the small latter ‘p’ .
Newton’s Second Law of Motion State that: ‘’The rate of change of momentum of a body is directly proportional to the applied force and takes place in the direction in which the force acts .’’