Mechanics: Properties of Matter, Force, Motion, and Energy

1. Force and Motion - PYQ Points

• Inertia: Inertia is related to Newton’s First Law of Motion. The inertia of an object depends on its mass.
• Impulse: Impulse is the product of force (F) and time (T). Hitting a ball with a bat and the use of shock absorbers in vehicles are related to this concept.
• Centrifugal Force: When a person moves from the poles toward the equator, the centrifugal force acting on him increases.
• Centripetal Force: A cyclist riding along a circular path leans inward to create the necessary centripetal force.
• Oscillatory Motion: Motion in which a body repeatedly moves back and forth about a fixed point.

2. Gravitation

• Newton’s Law of Gravitation: Explains the gravitational force between the Sun–Earth and Earth–Moon.
  W = mg (Relation between weight and acceleration due to gravity).
• Value of g: Variation in the value of g with time indicates seismic activity.
• Weightlessness: In outer space, in the absence of gravitational acceleration, a feeling of weightlessness is experienced.
• Centre of Gravity: The reason why a Thanjavur doll keeps oscillating without falling is due to its centre of gravity.

3. Properties