Physics, asked by lavieenrose, 11 months ago

examples of law of acceleration, law of action and reaction used in our daily life

Answers

Answered by Divesh121
2
If we just look around, we see many objects “at rest,” i.e., not moving. We know from a lifetime of empirical observation that those objects won’t move until some force—a push or a pull—causes that motion.

The second part of the law was actually what I consider to be a brilliant leap by Newton. Since the time of Aristotle, almost everyone believed that, for an object to keep moving, it needed to have some force continually applied to it. We see this happen everyday, even though Aristotle’s theory was entirely incorrect: For example, if we push a toy cart across the floor, it will come to rest unless we keep on pushing it. Newton’s insight was that thing cease moving only because of other forces—friction, air resistance, and the like. Without really knowing about the vacuum of space, Newton was able to envision an object set off in one direction and to conceive that it would continue at the same velocity forever unless it encountered some other object, gravity, or the like.

Everyday, we see this all the time, even without a vacuum. If you are traveling forward in a car and the car collides head-on with an object, the car is brought to a stop, but your body continues to travel forward in a straight line. This is experienced as being thrown forward against the seat-belt, airbag or, in the worst case, the hard dashboard of the car.

If you notice the words “unbalanced force,” that simply means forces that do not cancel one another out. For example, and object sitting on a table IS subject to external forces—the force of gravity pulling downward on it and the force of the table pushing upward on it (aka, the normal force). But, these two forces are exactly equal and opposite (see Newton’s 3rd law), and so they do not result in a change in the state of the object.

My favorite application of this law is removing ketchup from a bottle. If you invert the bottle with the cap on, and rapidly thrust it in a downward motion, then stop suddenly, Newton’s 1st law dictates that the ketchup itself will continue moving downward when you stop the bottle’s motion. When you open the bottle, the ketchup should be piled up at the top of the bottle and “squirtable.”

This law is also thought of as “inertia,” and is proportional to mass. Thus, as we see everyday, objects that we experience as “heavier,” i.e., those with more mass, are more difficult to push into motion from rest and are more difficult to stop when moving. Which brings us to the second law…

Newton’s 2nd law: A change in motion will be in the direction of the force applied and in proportion to the force applied.

This seems like commonsense to us: If I push an object, it travels in the direction I push it. If I push harder on an object, the change in direction or speed is more significant than if I had pushed softly on that object. Mathematically, Newton showed that the force applied to an object is directly proportional to its mass times its acceleration. If we rearrange the famous F=ma, we see that acceleration (that is, a change in either speed or direction or both) is directly proportional to the force applied and inversely proportional to the mass.

This is all just a mathematical way of saying that the harder we push or pull with a(n unbalanced) force, the more effect it will have. Push a ball softly, it accelerates a little bit. Push hard, it accelerates a lot more. The component of mass in the equation is likewise something we see everyday: It is harder to push a more massive object like a car than it is to push a less massive object like a basketball. Because the acceleration and forces considered are vectors, i.e., they have magnitude as well as direction, this law also describes changes in direction. Thus, it would be harder to change the direction, say, of a boulder than of a soccer ball.

Newton’s 3rd law: For every action there is an opposite and equal reaction.

Although this is often illustrated with the idea of a rocket in space spewing out exhaust (an action) and moving forward (the reaction), we also experience it every day on Earth. As suggested earlier, a mug sitting on a desk experiences two opposite and equal forces: The mug pushes down with the force of its weight (its mass times the acceleration caused by gravity), while the table pushes up with what is called the “normal” force. The forces are equal in magnitude and in opposite directions (the mug’s force is directed downward, and the desk’s force is directed upwards).

We also see this force in collisions: When two marbles collide with each other the first marble exerts a force—a push on the second marble to change its direction and speed. The second marble exerts an equal and opposite force on the first marble, and so they both careen off in opposite directions.

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Answered by sonabrainly
1

When you apply a force to the wall, simultaneously the wall reacts, isn’t it beautiful? As if the wall has its own will and does not want to move at all. It is like an uprising against you :D

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