First Law Of Motion Definition Class 9

Body at rest body in motion.

First law of motion definition class 9.

The first law of motion is stated as an object remains in a state of rest or of uniform motion in a straight line unless compelled to change that state by an applied force. The tendency of undisturbed objects whether they are at rest or moving with uniform velocity is called inertia. 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. 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 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. It requires some force from the outside to cause such a change. Velocity is a vector quantity which expresses both the object s speed and the direction of its motion.

There are two conditions. Newton s first law of motion gives the concept of inertia and force. Class 9 force and law of motion tagged with. The inability of any object to change its state is called inertia.

According to the law any object in the universe remains in its state of rest or uniform 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. Hence the first law of motion is also known as the law of inertia. All objects resist a change in their state of motion.

The first law of motion implies that things cannot start stop or change direction all by themselves. 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.