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

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

Tardigrade Admin · Accepted Answer

The arrangement is shown in figure.
Now draw the free body diagram of the spring balances and block.
For equilibrium of block,

T_{1} = M g

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} = M g

So, both scales read

M k g

.

Q. 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

both the scales read M kg each

the scale of the lower one reads M kg and of the upper one zero

the reading of the two scales can be anything but the sum of the readings will be M kg

both the scales read M / 2 kg