First Law Of Motion Definition Class 9

Newton s first law of motion.

First law of motion definition class 9.

It requires some force from the outside to cause such a change. Car or bus starts suddenly passengers fall backward galileo s law of inertia hanging carpet is beaten with stick inertia it is dangerous to jump out of moving bus its fruits and leaves fall down newton s first law of motion the dust particles start coming out of it tree is shaken vigorously. Newton s first law of motion gives the concept of inertia and force. All objects resist a change in their state of motion.

There are two conditions. Newton s first law of motion states that a body remains in the state of rest or uniform motion in a straight line unless and until an external force acts on it. Class 9 force and law of motion tagged with. Newton s first law states that if a body is at rest or moving at a constant speed in a straight line it will remain at rest or keep moving in a straight line at constant speed unless it is acted upon by a force this postulate is known as the law of inertia the law of inertia was first formulated by galileo galilei for horizontal motion on earth and was later generalized by rené descartes.

Hence the first law of motion is also known as the law of inertia. Body at rest body in motion. Therefore the statement that the object s velocity is constant is a statement that both its speed and the direction of its motion are constant. Inertia is of three types namely inertia of rest inertia of motion and inertia of direction.

The first law of motion implies that things cannot start stop or change direction all by themselves. Velocity is a vector quantity which expresses both the object s speed and the direction of its motion. The inability of any object to change its state is called inertia. The first law states that if the net force the vector sum of all forces acting on an object is zero then the velocity of the object is constant.

This property of massive bodies to resist changes in their state of motion is called inertia. Newton s first law of motion force and laws of motion get topics notes online test video lectures doubts and solutions for cbse class 9 on topperlearning.