Question

A wooden block of volume $1000c{m}^3$ is suspended from a spring balance. It weighs 12 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. 7 N

Answer 1

The correct option is D 7 N

Reading of the spring balance = Apparent weight of the block = Actual weight - upthrust = $12-V_{in}\sigma g=12-500\times {10}^{-6}\times {10}^3\times 10=12-5=7N$.