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The study material for CBSE Class 9 Laws of Motion can be accessed by the students on the Extramarks app. The app has a plethora of learning options that can be highly beneficial for the students. The students can have an ideal learning experience by studying on the app. The app can be a good learning companion for the students. Download the Extramarks learning app now.<br>
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Contact and Non-Contact Forces • Force is defined as an agent which changes or tends to change the state of rest or uniform motion of a body or changes its direction or shape. The SI unit of force is newton (N). In cgs system, force is measured in dyne. Force is the cause of motion of a stationary body, stopping, decreasing or increasing the speed of a body and change in the shape or size of a body. Force is further dived as Contact force: Contact force is defined as the force between two bodies when they are in physical contact. Non-contact force: Non-contact force is defined as the force between two bodies when they are not in physical contact.
First Law of Motion • Newton’s first law of motion is also known as law of inertia. Inertia of a body is defined as the tendency of the body to resist any change in its state of rest or motion. Mass is the measure of inertia of a body.Newton’s first law of motion states that every body resists a change in its state of rest or of uniform motion in a straight line unless acted upon by an external force. Inertia of three types:Inertia of rest: It is the inability of a body to change its state of rest by itself.Inertia of motion: It is the inability of a body to change its state of motion by itself.Inertia of direction: It is the inability of a body to change its state of direction by itself.
Second Law of Motion • Newton’s second law states that the rate of change of linear momentum of the body is directly proportional to the force applied on it and the change takes place in the direction of the applied force. In all the given examples, momentum is reduced thereby reducing the effect of force.
Third Law of Motion • Newton’s third law of motion states that for every action there is an equal and opposite reaction. Examples of Newton’s third law of motion are walking, recoil of gun and rocket propulsion. Action and reaction forces always react on the different bodies. A man leaving a boat and a boy hitting a wall are also examples of Newton’s third law of motion.
Extramarks’ Approach • The study material for CBSE Class 9 Laws of Motion can be accessed by the students on the Extramarks app. The app has a plethora of learning options that can be highly beneficial for the students. The students can have an ideal learning experience by studying on the app. The app can be a good learning companion for the students. Download the Extramarks learning app now. For more information visit and register at Extramarks website. https://www.extramarks.com/study-material/icse-class-9/physics-laws-of-motion