Science

Mass and inertia

In this Class 9 Science topic from “How Forces Affect Motion,” students explore how mass relates to an object’s resistance to changes in its motion. They learn that greater mass generally means greater inertia, and examine inertia of rest, motion, and direction through familiar examples such as passengers lurching when a bus starts or stops. The topic also connects these ideas with Newton’s first law and helps students explain everyday motion using clear scientific reasoning.