COM of Cavity & Truncated Bodies — JEE Main Physics MCQs with Solutions
Free JEE Main Physics COM of Cavity & Truncated Bodies MCQs with step-by-step solutions (2 questions). Part of Centre of Mass, Momentum & Collisions. Practise online on Prepizo — no login needed.
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Questions with solutions
Q1 — COM of Cavity & Truncated Bodies · easy · numerical
A uniform metre stick is cut at the 40 cm mark and the shorter piece is discarded. The COM of the remaining 60 cm piece (from its own left end at 40 cm) is at the stick mark:
A. 75 cm
B. 60 cm
C. 70 cm ✓ Correct
D. 80 cm
Solution: The 60 cm piece spans 40–100 cm; its midpoint is at 70 cm.
Q2 — COM of Cavity & Truncated Bodies · medium · numerical
From a disc of radius 6 cm, a hole of radius 2 cm is cut with its centre 3 cm from the disc centre. The COM shift of the remainder is:
A. 1/3 cm
B. 3/8 cm ✓ Correct
C. 3/4 cm
D. 1 cm
Solution: m_hole/M = 4/36 = 1/9; shift = (1/9 × 3)/(8/9) = 3/8 cm away from the hole.