Answer:
15.7 ; 78.5
Explanation:
Mechanical advantage of a screw = Circumference / pitch
Circumference = pi × d
Where :
pi = 3.142, D = diameter
Therefore ;
Circumference = 3.142 × (1/4) = 0.785 in
Pitch = 1/TPI
TPI (thread per inch) = 20
Pitch = 1/ 20 = 0.05
Mechanical advantage = 0.785 / 0.05 = 15.7
Resistance force if effort force is 5lb
Mechanical advantage = Fr / Fe
Fe = effort force, Fr = resistance force
15.7 = Fr / 5
Fr = 15.7 × 5 = 78.5 lbs
