A screw jack has a pitch of 12 mm with a mean radius of thread equal to 22.5 mm. A lever 600 mm long is used to raise a load of 1800 kg, the coefficient of friction is 0.10. Find the helix angle and friction angle.

A screw jack has a pitch of 12 mm with a mean radius of thread equal t

1.	A screw jack has a pitch of 12 mm with a mean radius of thread equal to 22.5 mm. A lever 600 mm long is used to raise a load of 1800 kg, the coefficient of friction is 0.10. Find the helix angle and friction angle.
A.	6.2° , 4.5°
B.	4.85°, 5.7°
C.	6.37°, 4.42°
D.	4.2°, 5.5°
Answer» C. 6.37°, 4.42°

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A screw jack has a pitch of 12 mm with a mean radius of thread equal to 22.5 mm. A lever 600 mm long is used to raise a load of 1800 kg, the coefficient of friction is 0.10. Find the helix angle and friction angle.

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