A) 0.1 m
B) 0.2 m
C) 0.3 m
D) 0.4 m
Correct Answer: D
Solution :
If student will try to answer it fastly he/she may calculate required extension y as \[\ge mg\Rightarrow y\ge 0.2m\]Hence option [B] is correct. Remember lower plate is lifted when upper plate is moving upward and spring is in extension condition. Compression at equilibrium \[y=\frac{mg}{k}=\frac{20}{100}=0.2\text{m}\]When extension will be equal to y then lower plate will be lifted and for this farther compression required is\[2y=2\times 0.2=0.4\,\,m\]You need to login to perform this action.
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