NCERT Solutions for Class 11 Physics Chapter 5
Q1: What are the various topics and subtopics in NCERT Solutions class 11 Physics chapter 5 laws of motion?
A1: The various topics and subtopics in NCERT Solutions class 11 Physics chapter 5 laws of motion are as given below:
5.2 Aristotle’s fallacy
5.3 The law of inertia
5.4 Newton’s first law of motion
5.5 Newton’s second law of motion
5.6 Newton’s third law of motion
5.7 Conservation of momentum
5.8 Equilibrium of a particle
5.9 Common forces in mechanics
5.10 Circular motion
5.11 Solving problems in mechanics.
Q2: State all Newton’s laws of motion.
A2: Newton’s First law of motion: Newton’s First law of motion states that a body continues to remain in the state of rest or uniform motion in a straight line until and unless an external force is applied on it.
Newton’s Second Law of motion: Newton’s Second Law of motion states that the acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object.
Newton’s Third Law of motion: Newton’s Third Law of motion states that every action has an equal and opposite reaction.
Q3: Give a few examples regarding Newton’s third law of motion.
A3: few examples regarding Newton’s third law of motion are as follows:
A moving or navigation of fish through water is an ideal example of an action-reaction pair. A fish makes use of its fins to push the water backwards. This push is the action that serves to accelerate the fish forwards which is the equivalent reaction. The magnitude of the force on the water equals the magnitude of the force on the fish. The direction of the force on the water (backwards) is opposite in the direction of the force on the fish (forwards).
The flight of the bird is another example of an action-reaction pair. The wings of the bird push the air downwards which is the action. The air pushes the bird upwards which is the equal and opposite reaction.
A swimmer pushes against the water which is the action. In return, the water pushes the swimmer front which the equal and opposite reaction.
Helicopters lift off the ground, by pushing the air down. Pushing the air below by the blades is the necessary action while creating an upward force which lifts up the helicopter as the equal and opposite reaction.
Rock climbers pull their vertical rope downwards as an action. An equal and opposite reaction is obtained in the form of a push they get for themselves in the upward direction.
Q4: What is a force? What are the various parameters related to force?
A4: We can say that force is a push or pull acting on an object or energy as an attribute of physical action or movement. This occurs when two entities are in contact. According to the universal law of gravitation, every object in this universe exerts a force on others. The force acting on an object is given by the following parameter:
SI unit of Force: newton(N) or kg.m/s2
Symbol of Force: F
Type of quantity: Vector quantity
Dimensional Formula: M1L1T-2
Other units: dyne, pound-force, kilopond, poundal, kip