 
			 
			MCQOPTIONS
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				| 1. | In a screw jack, the effort required to lift the load is given by(where W = Load lifted, α = Helix angle, and φ = Angle of friction.) | 
| A. | P = W tan (α - φ) | 
| B. | P = W tan (α + φ) | 
| C. | P = W tan (φ - α) | 
| D. | P = W cos (α + φ) | 
| Answer» C. P = W tan (φ - α) | |