Newton’s First Law of Motion (Law of Inertia)
Statement: An object at rest stays at rest, and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced external force.
Explanation: This law introduces the concept of inertia, which is the tendency of objects to resist changes in their state of motion. Essentially, if no net force acts on an object, its velocity will remain constant.
Example: A book lying on a table will remain stationary unless a force, like a push, moves it. Similarly, a rolling ball will continue to roll at a constant velocity unless friction or another force slows it down.
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Newton’s Second Law of Motion
Statement: The acceleration of an object is directly proportional to the net force acting on the object and inversely proportional to the object’s mass. The direction of the acceleration is in the direction of the net force acting on the object.
Mathematical Formulation: F=maF = maF=ma
- FFF is the net force applied to the object.
- mmm is the mass of the object.
- aaa is the acceleration of the object.
Explanation: This law quantifies the effect of forces on an object’s motion. It tells us that the greater the force applied to an object, the greater its acceleration, and that heavier objects (with more mass) require more force to achieve the same acceleration as lighter objects.
Example: Pushing a car (which has a large mass) requires more force to accelerate than pushing a bicycle (which has a smaller mass).
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Newton’s Third Law of Motion
Statement: For every action, there is an equal and opposite reaction.
Explanation: This law means that forces always come in pairs. If one object exerts a force on a second object, the second object exerts an equal force in the opposite direction on the first object.
Example: When you jump off a boat onto the dock, you push the boat away from you. The force you exert on the boat (action) results in an equal and opposite force exerted by the boat on you (reaction), propelling you forward onto the dock.
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