Task $2\mathrm{.}1$

A lead screw has square threads with a pitch of $3$ mm and a mean diameter of $14$ mm $.$ Coefficient of friction is $0\mathrm{.}25.$ The load is $300$ kg $.$

Calculate:

a$)$ the force required to turn the lead screw

b$)$ the torque required to turn the lead screw

c$)$ the operating efficiency

Task $2\mathrm{.}2$

A screw jack has a single start thread of pitch $10$ mm and is used to raise a load of $500$ kg $.$ The required effort is $55$ N which is applied at the end of an operating handle $200$ mm long.

Calculate:

a$)$ the mechanical advantage

b$)$ the velocity ratio

c$)$ the operating efficiency