Chapter 5 Newton's law of motion comprises all the three laws of motion and a few essential terms required to determine the unknown. The first law of motion lays out that an object at rest or in uniform motion will continue to be in the same state until an external force acts on it. When the net force acting on a body is zero, it tends to maintain constant velocity rather than changing it. However, on applying additional force, the velocity changes.
Newton's second law states that the acceleration of an object in motion is inversely proportional to its mass. Moreover, the law stipulates that the net force produced is proportional to the magnitude and is in the same direction as the force. It indicates how much an object can accelerate for a given amount of force accurately. The formula for Newton's second law of motion is given as F=kma
Here, k denotes the constant of proportionality and is equal to 1 when the values are expressed in the SI system. Thus, the final expression will be given by F=ma Newton's third law of motion says that there is an equal and opposite reaction for every action. Thus, when two bodies interact, they apply an equal and opposite force on each other. The chapter further discusses the concepts of tension and acceleration.
The force of tension usually transmits along a string, wire or a rope because of the force which is acting on the other side. This force acts equally on both the ends of the wire. Tension on an object can be mathematically expressed as T = mg + ma
The functioning of an elevator can perfectly describe Newton's second law of motion. When the elevator is accelerating upwards, we may feel heavier than usual. On the contrary, we feel lighter when accelerating downwards. If the elevator cable broke, we would be accelerating downwards along with the elevator at the same rate. Thus, we would feel weightless.