Per NCERT §4.7, the total momentum of an ISOLATED system (no external force) is which?
AAlways increasing
BAlways zero
COnly the speed is conserved
DConserved
Answer & Solution
Correct answer: D. Conserved
NCERT §4.7: F_ext = 0 ⇒ dP_total/dt = 0 ⇒ P_total constant. Holds in any inertial frame; valid for elastic AND inelastic collisions.
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