Sir Isaac Newton(1642-1727) was one of the most brilliant of all scientists. One of his greatest achievements was to work out the laws of motion and gravity. These affect everything in the Universe, from atoms and grains of sands, to the Earth, Moon, stars and galaxies in space. These three basic ideas are applied to the physics of motion. The ideas have been tested and verified so many times over the years, that scientists now call them Newton's Three Laws of Motion.
Law 1: Keep on keeping on: The first law says that an object at rest tends to stay at rest, and an object in motion tends to stay in motion, with the same direction and speed. Motion (or lack of motion) cannot change without an unbalanced force acting. If nothing is happening to you, and nothing does happen, you will never go anywhere. If you're going in a specific direction, unless something happens to you, you will always go in that direction; for forever.
Law 2: More means faster: The second law says that greater the force on an object, the faster the object picks up speed. That is, acceleration of an object is proportional to the force acting upon it. The second law shows a example that if you exert the same force on two objects of different mass, you will get different accelerations. The acceleration on the smaller mass will be greater. The effect of a 10 newton force on a baseball would be much greater than that same force acting on a truck. The difference in effect (acceleration) is entirely due to the difference in their masses.
Law 3: Bouncing back of opposite forces: The third law says that for every action (force) there is an equal and opposite reaction (force). Forces are found in pairs. Think about the time you sit in a chair. Your body exerts a force downward and that chair needs to exert an equal force upward or the chair will collapse. It's an issue of symmetry. Acting forces encounter other forces in the opposite direction. There's also the example of shooting a cannonball. When the cannonball is fired through the air (by the explosion), the cannon is pushed backward. The force pushing the ball out was equal to the force pushing the cannon back, but the effect on the cannon is less noticeable because it has a much larger mass. That example is similar to the kick when a gun fires a bullet forward.
Videos - For visual understanding
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https://www.youtube.com/watch?v=LEHR8YQNm_Q
https://www.youtube.com/watch?v=ZvPrn3aBQG8
https://www.youtube.com/watch?v=EgqcGrB3re8
Law 1: Keep on keeping on: The first law says that an object at rest tends to stay at rest, and an object in motion tends to stay in motion, with the same direction and speed. Motion (or lack of motion) cannot change without an unbalanced force acting. If nothing is happening to you, and nothing does happen, you will never go anywhere. If you're going in a specific direction, unless something happens to you, you will always go in that direction; for forever.
Law 2: More means faster: The second law says that greater the force on an object, the faster the object picks up speed. That is, acceleration of an object is proportional to the force acting upon it. The second law shows a example that if you exert the same force on two objects of different mass, you will get different accelerations. The acceleration on the smaller mass will be greater. The effect of a 10 newton force on a baseball would be much greater than that same force acting on a truck. The difference in effect (acceleration) is entirely due to the difference in their masses.
Law 3: Bouncing back of opposite forces: The third law says that for every action (force) there is an equal and opposite reaction (force). Forces are found in pairs. Think about the time you sit in a chair. Your body exerts a force downward and that chair needs to exert an equal force upward or the chair will collapse. It's an issue of symmetry. Acting forces encounter other forces in the opposite direction. There's also the example of shooting a cannonball. When the cannonball is fired through the air (by the explosion), the cannon is pushed backward. The force pushing the ball out was equal to the force pushing the cannon back, but the effect on the cannon is less noticeable because it has a much larger mass. That example is similar to the kick when a gun fires a bullet forward.
Videos - For visual understanding
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https://www.youtube.com/watch?v=LEHR8YQNm_Q
https://www.youtube.com/watch?v=ZvPrn3aBQG8
https://www.youtube.com/watch?v=EgqcGrB3re8