A screw jack can raise or lower a heavy load (1,653 N) using a smaller effort. However, they are very inefficient machines due to their high friction. Also, their efficiency is lower when raising a load than it is when lowering the same load.

The pitch, of a single start thread on a 35.5 mm radius screw, is 9.02 mm. When raising or lowering a load, this screw is respectively 11.73 % or 15.77 % efficient.

All answers have a tolerance of 1 on the third significant figure.

The radius of the effort applied perpendicular to the handle is 318 mm.

a) Calculate the screw's lead.

b) Calculate the screw jacks's IMA.

c) Calculate the minimum effort applied to the handle to raise a 1,653 N load.