Question

A light spring balance hangs from the hook of the other light spring balance and a block of mass M kg hangs from the former one. Then the true statement about the scale reading is

• A. both the scales read M kg each
• B. the scale of the lower one reads M kg and of the upper one zero
• C. the reading of the two scales can be anything but the sum of the readings will be M kg
• D. both the scales read M / 2 kg

Answer 1

Answer: (A)

both the scales read M kg each

Answer 2

The arrangement is shown in figure.Now draw the free body diagram of the spring balances and block.For equilibrium of block, ${{T}_{1}}=Mg$ where ${{T}_{1}}=$ Reading of ${{S}_{2}}$ For equilibrium of ${{S}_{2}},\,\,{{T}_{2}}={{T}_{1}}$ where ${{T}_{2}}=$ Reading of ${{S}_{1}}$ For equilibrium of ${{S}_{1}},\,\,{{T}_{2}}={{T}_{3}}$ Hence, ${{T}_{1}}={{T}_{2}}=Mg$ So, both scales read $M\,\,kg$ .