Q1
Newton's second law is expressed as:
AF=ma
BF=ma²
CF=m/a
DF=a/m
CBSEClass 9 (CBSE)ScienceCh 8 · Topic 1
Newton's First and Second Laws
Learning the first two laws of motion proposed by Newton.
Core concept
Inertia is the natural tendency of an object to resist a change in its state of motion, and it is directly proportional to an object's mass — heavier objects have more inertia and are harder to start or stop moving. Newton's Second Law explains why the same force produces greater acceleration on a lighter object than a heavier one, and it is used to calculate exact force requirements in engineering, from designing car brakes to calculating rocket thrust needed to reach orbit.
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• Newton's First Law (inertia): objects resist changes to their motion unless acted upon by an unbalanced force.
• Inertia is proportional to mass — heavier objects have more inertia.
• Newton's Second Law: F = ma (Force = mass × acceleration).
• The same force produces greater acceleration on a lighter object than a heavier one.