Question Number 21516 by Tinkutara last updated on 26/Sep/17
$$\mathrm{A}\:\mathrm{5}-\mathrm{kg}\:\mathrm{body}\:\mathrm{is}\:\mathrm{suspended}\:\mathrm{from}\:\mathrm{a}\:\mathrm{spring}- \\ $$$$\mathrm{balance},\:\mathrm{and}\:\mathrm{an}\:\mathrm{identical}\:\mathrm{body}\:\mathrm{is} \\ $$$$\mathrm{balanced}\:\mathrm{on}\:\mathrm{a}\:\mathrm{pan}\:\mathrm{of}\:\mathrm{a}\:\mathrm{physical} \\ $$$$\mathrm{balance}.\:\mathrm{If}\:\mathrm{both}\:\mathrm{the}\:\mathrm{balances}\:\mathrm{are}\:\mathrm{kept} \\ $$$$\mathrm{in}\:\mathrm{an}\:\mathrm{elevator},\:\mathrm{then}\:\mathrm{what}\:\mathrm{would}\:\mathrm{happen} \\ $$$$\mathrm{in}\:\mathrm{each}\:\mathrm{case}\:\mathrm{when}\:\mathrm{the}\:\mathrm{elevator}\:\mathrm{is}\:\mathrm{moving} \\ $$$$\mathrm{with}\:\mathrm{an}\:\mathrm{upward}\:\mathrm{acceleration}? \\ $$
Answered by ajfour last updated on 26/Sep/17
$${mg}\rightarrow{m}\left({g}+{a}\right) \\ $$$$\Rightarrow\:{spring}\:{balance}\:{has}\:{new}\:{equili}- \\ $$$${brium}\:{point}\:\left({stretches}\right). \\ $$$${Physical}\:{balance}\:{remains}\: \\ $$$${balanced}\:{with}\:{the}\:{same}\:{weights}. \\ $$
Commented by Tinkutara last updated on 26/Sep/17
$$\mathrm{Thank}\:\mathrm{you}\:\mathrm{very}\:\mathrm{much}\:\mathrm{Sir}! \\ $$
Commented by Tinkutara last updated on 27/Sep/17
$$\mathrm{ajfour}\:\mathrm{Sir},\:\mathrm{can}\:\mathrm{you}\:\mathrm{see}\:\mathrm{Q}.\:\mathrm{21307}? \\ $$
Answered by revenge last updated on 27/Sep/17
$$\mathrm{In}\:\mathrm{first}\:\mathrm{case},\:\mathrm{the}\:\mathrm{reading}\:\mathrm{of}\:\mathrm{spring}\:\mathrm{balance}\:\mathrm{increases}\:\mathrm{but}\:\mathrm{in} \\ $$$$\mathrm{second},\:\mathrm{there}\:\mathrm{will}\:\mathrm{be}\:\mathrm{no}\:\mathrm{effect}\:\mathrm{on}\:\mathrm{physical}\:\mathrm{balance}\:\mathrm{because} \\ $$$$\mathrm{on}\:\mathrm{both}\:\mathrm{sides}\:\mathrm{of}\:\mathrm{physical}\:\mathrm{balance},\:\mathrm{there}\:\mathrm{are}\:\mathrm{equal}\:\mathrm{masses}. \\ $$
Commented by Tinkutara last updated on 27/Sep/17
$$\mathrm{Thank}\:\mathrm{you}\:\mathrm{very}\:\mathrm{much}\:\mathrm{Sir}! \\ $$