Laws Of Motion Class 11 Notes

What is Inertia?

The property of an object by virtue of which it cannot change its state of uniform motion along a straight line or rest on its own is called as inertia.It is the measure of the mass of a body. There are 3 types of inertia.

  • Inertia of rest
  • Inertia of motion
  • Inertia of direction

What is Force?

A force is a push or pull upon an object resulting from the object’s interaction with another object.Force can be categorized into two types;

  • Constant Force
  • Action at a distance force

What are Newton’s Laws of Motion?

  1. First Law:“A body continues in its state of rest or of uniform motion in a straight line unless it is compelled by some external force to change that state.”
  2. Second Law:“The rate of change of momentum of a body is directly proportional to the impressed force and takes place in the direction of the force.”
  3. Third Law:“To every action, there is an equal and opposite reaction.”Important Questions
  1. Aristotle’s view that a force is necessary to keep a body in uniform motion is wrong. A force is necessary for the practice to counter the opposing force of friction.
  1. Galileo extrapolated simple observations on motion of bodies on inclined planes, and arrived at the law of inertia. Newton’s first law of motion is the same law rephrased thus: “Everybody continues to be in its state of rest or of uniform motion in a straight line unless compelled by some external force to act otherwise”. In simple terms, the First Law is “If the external force on a body is zero, its acceleration is zero”.
  1. Momentum (p ) of a body is the product of its mass (m) and velocity (v) :p = mv

Do check out the given links to know more about the topics in detail. Inertia Force Laws of Motion Newton’s First Laws of Motion, Newton’s Second Laws of Motion, Newton’s Third Laws of Motion

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Practise This Question

Which of the following hormone sequences is correct?