force and laws of motion

CHAPTER AT A GLANCE
1. Dynamics is the study of the motion of bodies while taking onto account the cause of motion ie force.
2. force is an agent whose action can produce acceleration in a body.
3. Inertia is the ability of a body be virtue of which it opposes any change in its state of rest or uniform motion.
4. The inherent property of a body by virtue of which it cannot change its state of rest is called INERTIA OF REST.
5.The inherent property of a body by virtue of which it cannot change its state of motion is called INERTIA OF MOTION.
6.The inherent property of a body by virtue of which it cannot change its state of direction is called INERTIA OF direction.


NEWTON"S FIRST LAW OF MOTION
It states that "An object at rest stays at rest or an object in motion, stays in motion (in the same direction/at the same speed) unless acted upon by an unbalanced force."
Also called the law of inertia


MOMENTUM
The total quantity of motion possessed by the body is called momentum.

Mathematically, momentum is Calculated by: P = mv
(p = momentum, m = mass, v = velocity)

NEWTON"S SECOND LAW OF MOTION

It states that" The rate of change of momentum is directly proportional to the applied unbalanced force in the direction of force."

Mathematically, F= m x a

Gravitational unit of force is Kilogram force(Kgf)

1 Kgf = 1 kg x 9.8 m/s2
= 9.8 N
NEWTON"S THIRD LAW OF MOTION

It states that " To every action there is an equal and opposite reaction"

A SINGLE ISOLATED FORCE DOESNT EXIST IN NATURE.

EFFECTS OF FORCE
1. Can produce motion in stationary bodies.
2. Can Stop a moving body.
3. Can change the speed and direction of the moving body.
4. can bring about change in the dimensions of the moving body.