Define Force and Laws of motion in Physics

Updated on Jan. 8, 2021 03:25 PM IST by Lakshmi Arya

A force is the change of state of an object due to external surroundings. Due to forces, an object will either be in a state of motion or will be resting.

we always need to apply force to make anything to move, to stop or change its direction or change the shape of an object. Like, to change the shape of a Rubber band, to knead the dough, push a trolley, stop a moving car by applying break, etc. But many times even on applying force the object does not move at all. For example- If two person push a heavy table /object from opposite sides or Two  team pull the rope with equal force in a tug of war game, we find that the table or rope does not move. When two persons push the heavy table with equal force from opposite directions, their forces get balanced, the net force on the table or rope is zero. Therefore the table or rope does not move at all. When two forces equal in magnitude are applied on an object through push or pull from opposite directions, and the resultant force on the object is zero. such force is called Balanced force. The rope or table moves only when the applied force of both persons is getting unbalanced by applying force either in the same direction or when gone of them applies more force than the other. such force is known as an unbalanced force

Few points on Force:--

  1. An unbalanced force acting on an object brings it in motion.
  2. To move an object the applied force must unbalance its frictional force
  3. A force never acts alone. Force always exists in pairs. This pair of forces act in opposite direction. Whenever one of the  forces is greater than the other, there is a motion.
  4. To accelerates the motion of an object an unbalanced force is required.

Inertia:-- The natural tendency of an object to resist a change in their state of uniform motion or of rest is called inertia.

  1. Every object opposes the changes in its state of motion. It tends to remain in its state of rest or motion.
  2. The mass of an object is a measure of its inertia.
  3. Heavier object will have larger inertia in comparison to the lighter object, due to which we need to apply more force to change their state of motion.
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