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Newton 1st law |
| Answer» Definition:“A body remains in the state of rest or uniform motion in a straight line unless and until an external force acts on it.”Putting Newton’s first law in simple words, a body will not start moving until and unless an external force acts on it. Once it is set in motion,it won’t stop or change its velocity until and unless some force acts upon it once more. Let us understand Newton’s First Law of Motion by an example: Let’s take a block on a smooth surface. By smooth, we mean that there is no friction acting on the surface. The block is at rest, that is, it is not moving.Now, let’s examine the forces acting on the block. The only forces acting on the block are the force of gravity and the normal reaction by the surface. There is no force acting on it in the horizontal direction. Since the forces in the vertical direction are equal to each other in magnitude, they cancel each other out, and hence there is no external force on the block. Since this block is at rest, we can say that it confirms Newton’s first law of Motion.Newton’s First LawNow, if we apply a constant force F on the block in horizontal direction, it will start moving with some constant acceleration, in the direction of the applied force.Newton’s First LawThus, Newton’s first law is confirmed again.Note: Newton’s laws are valid only in inertial frames of reference. Examples of Newton’s First Law of Motion in daily life: Wearing a seat belt in a car while driving is an example | |