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The radius of gyration of a solid sphere of mass 5 kg about XY is 5 m as shown in figure. The radius of the sphere is (5x)/(√7) m, then the value of x is:

Asked in Re-NEET 2024 · Radius of gyration and numericals

• (1) 5
• (2) √2
• (3) √3
• (4) √5

Step-by-step solution

Why the other options are wrong

• (1) x=5 would make the radius (25)/(√7)≈9.4 m, larger than the 5 m radius of gyration about a tangent; about a tangent K always exceeds R.
• (2) No single slip gives √2; about a tangent K²=7/5R², which gives R=5√5/7.
• (3) No single slip gives √3; about a tangent K²=7/5R², which gives R=5√5/7.

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