The passenger tends to lean forward when a running metro stops suddenly. It is because of

CONCEPT:

• Newton’s First Law: A body continues to be in its state of rest or of uniform motion along a straight line unless it is acted upon by some external force to change the state.
  • If no net force acts on a body, then the velocity of the body cannot change i.e. the body cannot accelerate.
  • Newton’s first law defines inertia and is rightly called the law of inertia.
• The inertia of motion: It is the inability of a body to change by itself its state of uniform motion i.e., a body in uniform motion can neither accelerate nor retard on its own.

EXPLANATION:

• When the running metro stops suddenly, the passenger tends to lean forward because the lower part of his body comes to rest with the ground but the upper part tends to continue its motion due to inertia of motion. Hence option 3 is correct.