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Short Summary of Force and Laws of Motion


The effects which cause the state of motion changes or try to change, then, the effect is called Force. It is denoted by F. The S.I. unit of Force is newton (N). 


When force applied on a body

  1. Rest state is in now moving
  2. Change the velocity of object, either increase or decrease.
  3. Change the direct of motion
  4. Can change the shape of object

Balanced Force: If the equal amount of any opposite force is applied on a body that causes the state of motion of that body will not change is called Balanced Force. They can’t change the state of motion but can change the shape of object

Unbalanced Force: If the opposite forces are not equal then, it is called unbalanced force. They can change the state of motion and may change the shape of motion. It is used for accelerate/decelerate the motion

Frictional Force: The force of friction is due to the surface of contact between body and ground. It always act on the opposite direction of motion. It depends on the smoothness of surface and the mass of object.

Net Force: If the more number of forces applied on an object, the their resultant force is called the net force. The net force of balanced force is always 0. While for unbalanced it is non-zero

1st Law of Motion

Based on the Galileo Observation Newton Gives the three fundamental laws of motion.

According to Newton, the 1st law of motion states that, everybody will always be in rest or in uniform velocity in a straight line, unless compelled to change its state by the action of external force. This is also called the law of inertia.

Inertia: According to the 1st law of motion, everybody never wants to change its state. So, we can say that there are some internal force is acted on the body whose tendency to resist the external force.So, the internal force of a body who resist the external force to change the state of body is called the inertia of the body.

2nd Law of Motion

2nd law explains that the rate of change in momentum is directly proportional to the applied force. It is denoted by F. The S.I. Unit of force is N.

3rd law of Motion

Third law of motion states that, when a object exert an amount of force on another object, then the 2nd object also exert same amount of force on the first object.

In other word, every reaction has equal and opposite reaction. In the game of football sometimes we, while looking at the football and trying to kick it with a greater force, collide with a player of the opposite team. Both feel hurt because each applies a force to the other

Conservation of Momentum

The total momentum of any system is always conserved. Let us consider an elastic collision, then according to law of conservation

total momentum before the collision = total momentum after the collision.

(For Complete Notes of Force and Laws of Motion Download the PDF by clicking download at the beginning of this article.)


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