Question

A wooden block of volume $1000c{m}^3$ is suspended from a spring balance. It weighs 10 N in air. It is suspended in water such that half of the block is below the surface of water. The reading of the spring balance is

• A. 10 N
• B. 9 N
• C. 8 N
• D. 5 N

Answer 1

The correct option is D 5 N

Reading of the spring balance
= Apparent weight of the block
= Actual weight – upthrust
$=10-V_{in}\sigma g=10-500\times {10}^{-6}\times {10}^3\times 10=10-5=5N$