A single square$-$threaded power screw is $25mm$ in diameter

with a lead distance of $5mm.$ A vertical load $(P)$ on the

screw reaches a maximum of $5kN.$ The coefficients of

friction are $0\mathrm{.}09$ for the threads and $0\mathrm{.}06$ for the collar. The

frictional diameter of the collar is $45mm.$ The torque to

"raise" the load is

$($a$)7,83Nm$

$($b$)7\mathrm{.}65N*m$

$($c$)10\mathrm{.}43N*m$

$($d$)15,85Nm$