Forces
Have you ever wondered what causes the stationary truck to move? Why do all the planets revolve around sun? Why does an object start movie? Why does the speed of object change with time? Why do all the planets revolve around the sun?
The answer of These question is Force.
As you may have already learned force is any push or pull which tries to change the shape, size, state of the object. Force can bring a stationary object at rest and an object at rest in motion.
Sometimes forces may be acting a body but it's effect may zero. let us understand the balanced and unbalacned forces
Let's first understand about the balanced and unbalanced forces.
What are the balanced forces?
When two equal and opposite forces act on the same object at one point, their net effect is zero this is called as balance force. For example the forces acting on the car will cancel each other so there effect will be zero. so they are not effective
What is net force?
Net force can be found by adding two or more forces acting on the object.
If two forces F1 and F2 act on an object then the net force
Fnet = F1+ F2
In case of opposite forces
Fnet = F1- F2 or Fnet = F2-F1
What is unbalanced force?
When two unequal and opposite forces act on the same object at a point they do not cancel each other completely this is called as unbalance force.
For example; when a 50N of force is applied from left side and 30N is applied from right side on a stationary truck they do not cancel each other completely. There will be a net force of 20N acting towards the right side.
First law of motion or Newton's First Law or Law of Inertia
According to the first law of motion "all the bodies try to remain in their initial state until and unless an external force is applied on it."
It means " if a body is in motion it wants to continue in the motion and if a body is at rest it wants to stay at rest until and unless some external agency applies the external force."
For example:
The book kept on the table be a stay on the table.
Glass kept in the kitchen will always stay in the kitchen until an unless someone comes and disturbs their position.
If a car is moving in absence of friction then it will continue to move unless some external force acts in opposite direction of it's motion
Newtons second law or The Second Law of Motion
According to Newton's second law, "the rate of change of momentum is directly proportional to the applied and balance force."
For example:
when a cricketer catches the ball, to increase the impact time he pulls his hand backward. This decreases the force applied by the ball on his hands.
To make the landing smooth we jump on the cushion.
Newton's 3rd law or Third law of Motion
According to Newton's third law, " for every action there is always equal and opposite reaction."
For example:
If a person hit the wall, the wall also applies the reaction force and person gets furt.
To move forward we apply backward force on the earth in turn earth also applies creation force and we move forward. If we try to move on the sand then it's not easy to move on sand because our legs go down into the sand and the reaction force applied by the sand is smaller.
So when the action is less reaction will be less and when action is greater reaction will also be greater. These are very much laws of nature.
