Question Number 6767 by Tawakalitu. last updated on 24/Jul/16
$${A}\:{molten}\:\:{plastic}\:{flows}\:{out}\:{of}\:{a}\:{tube}\:{that}\:{is}\:\mathrm{8}.\mathrm{0}{cm}\:{long} \\ $$$${at}\:{a}\:{rate}\:{of}\:\mathrm{13}{cm}^{\mathrm{3}} /{min},\:{when}\:{the}\:{pressure}\:{differential} \\ $$$${between}\:{the}\:{two}\:{ends}\:{of}\:{the}\:{tube}\:{is}\:\mathrm{18}{cm}\:{mercury}. \\ $$$${find}\:{the}\:{viscousity}\:{of}\:{the}\:{plastic}.\: \\ $$$${The}\:{internal}\:{diameter}\:{of}\:{the}\:{tube}\:{is}\:\:\mathrm{1}.\mathrm{30}{mm}.\: \\ $$$${the}\:{density}\:{of}\:{mercury}\:{is}\:\mathrm{13}.\mathrm{6}{g}/{cm}^{\mathrm{3}} \\ $$