Force and Laws of Motion

The concept of force is based on the process of push, hit, or pull. A force can be used to change the magnitude of the velocity of an object (to make the object move faster or slower) or to change its direction of motion. When a  force is applied to an object, it can change the shape and size of objects.

Balanced and Unbalanced Forces:

• Balanced forces: If equal forces are applied to an object in a different direction, the object will not move. Such forces are called balanced forces.
  • These forces have the ability that they can not change the state of rest or of motion of an object
• Unbalanced Forces: If two opposite forces of different magnitudes are applied to an object, then the object would begin to move in the direction of the greater force

First Law of Motion:

It expresses that ‘An item keeps on being in a condition of rest or of uniform motion along a straight line except if followed up on by an uneven power’

• In other words, it can also be written as objects resisting a change in their state of motion
• The ‘main law of movement’ is otherwise called the ‘law of inactivity’

Inertia and Mass:

Inertia is a natural tendency of objects to resist changes in their resting state or uniform motion. The inertia of an object is the property measured by its mass.

Second Law of Motion:

According to this law, the rate of change of momentum of an object has a direct relation with the applied unbalanced force. It has the direction of the force.

• The force (F) acting on an object is directly proportional to the product of the mass (m) of the object and the acceleration (a) produced on it

F ∝ m × a, or F = k m a

      F = ma (Value of k is 1 in SI system)

• • SI unit of force is (kg m s–2).  The unit of force is  Newton and is simply represented by the symbol N
• One Newton of force produces an acceleration of 1 m s–2 on an object having a  mass of  1 kg

Momentum:

 Momentum symbolically written as (p) and is defined as the product of its mass, m, and velocity, v.

Hence,

p = mv

• The course of force is as old as of speed, v
• Momentum has a unit as   (kg m s^-1)

Third Law of Motion:

It states that ‘To every action, there is an equal and opposite reaction, and they act on two different bodies.

When one thing pushes on another, the other immediately pushes on the first

• They have equal magnitude but will have opposite directions
• These two forces act on various different objects and can never be applied to the same object

Conservation of Momentum:

Total momentum remains conserved in an isolated system (where there is no external force).

• The sum of the moments of two objects before the collision is equal to the sum of the moments after the collision provided that no external unbalanced force is acting on them
• This is known as the ‘law of preservation of energy

Conclusion:

Motion and forces are something that we experience in our daily life but we do not know the law working behind it. Laws of motion are important as they define the working principle behind the force and its types. According to this article, forces are of 2 types: Balanced force & Unbalanced force.

The first law of motion states that ‘An item keeps on being in a condition of rest or of uniform motion along a straight line except if followed up on by an uneven force.’

The second law of motion claims that ‘the rate of change of momentum of an object has a direct relation with the applied unbalanced force.’

The third law of motion says that ‘To every action, there is an equal and opposite reaction, and they act on two different bodies.’