BharatNotes Inertia
nounUsage in a UPSC answer
The reform foundered less on overt opposition than on bureaucratic inertia, as entrenched procedures and a risk-averse establishment quietly resisted every attempt to alter the status quo.
Synonyms
Antonyms
Word Family
inert (adj), inertial (adj), inertly (adv), inertness (n), inertial (adj)
Root
Latin inertia = inactivity; iners = idle, sluggish; in- = not + ars = skill, art
Etymology
From Latin inertia ("lack of skill, inactivity"), from iners ("idle, sluggish"), from in- ("not") + ars ("skill, art").
Memory Hook
Break it into in- ("not") + art ("skill/action") — one who is "in-ert" takes no action; inertia is the state of not acting, of staying put.
How This Word Works in UPSC Writing
The property by which a body resists any change to its state of rest or uniform motion. Newton's first law is the law of inertia, and it does more than describe behaviour: it overturns the older Aristotelian assumption that force is needed to sustain motion, establishing instead that force is needed only to change it, which is why a body in space continues indefinitely without propulsion. Mass is the quantitative measure of inertia, which is why a loaded truck is harder both to start and to stop than an empty one. The three familiar forms are worth separating: inertia of rest, seen when dust flies from a beaten carpet or passengers lurch backward as a bus starts; inertia of motion, seen when they pitch forward as it brakes; and inertia of direction, seen when they are thrown outward on a turn.
Don’t Confuse It With
Inertia is the tendency to resist change in the state of motion, and mass is its measure, which is why mass is unchanged by location while weight, being the gravitational force on that mass, is not. Momentum is the motion a body actually possesses rather than its resistance to change. Friction is an external force opposing relative motion and is frequently mistaken for inertia in everyday explanations. A pseudo-force such as centrifugal force appears only when observations are made from an accelerating frame, and unlike a real force it has no reaction pair.
Hindi Meaning
जड़त्व (jadatva); जड़त्व आघूर्ण for moment of inertia.
Common Questions
- What are the three types of inertia?
- Inertia of rest, inertia of motion and inertia of direction, illustrated respectively by a passenger lurching back as a bus starts, forward as it brakes, and outward as it turns.
- What is the difference between mass and weight?
- Mass is the amount of matter and the measure of inertia, and does not change with location, while weight is the gravitational force acting on that mass and varies from place to place.
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