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Question
A 20 N metal block is suspended by a spring balance. A beaker containing some water is placed on a weighing machine which reads 40 N. The spring balance is now lowered so that the block gets immersed in the water. The spring balance now reads 16 N. The reading of the weighing machine will be
Options
36 N
60 N
44 N
56 N
Solution
44 N
Upthrust exerted by the water on the block = Change in the reading of the spring balance
= (20 − 16) N = 4 N
Downthrust = 4 N
Actual weight of the beaker containing water = 40 N
∴ Effective weight = (40 + 4) N = 44 N
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