Answer:
18.75in
Explanation:
Modulus of elasticity = Stress/Strain
Since stress = Force/Area
Given
Force = 1000lb
Area = 0.75sqin
Stress = 1000/0.75
Stress = 1333.33lbsqin
Strain
Strain = Stress/Modulus of elasticity
Strain = 1333.33/5,000,000
Strain = 0.0002667
Also
Strain = extension/original length
extension = 0.005in
Original length = extension/strain
Original length = 0.005/0.0002667
Original length = 18.75in
Hence the original length of the rectangular bar is 18.75in
Answer:
(d) all of the above
Explanation:
before cutting the screw threads the operator should lubricate all of the machine parts given in the option that is lead screw and gearbox , the ways and the cross slide and the carriage and half-nuts. we should use lubrication because it reduces the overall system friction and if friction is reduced then heat generated due to friction is also decreases which is beneficial
so option (D) will be correct because we need lubricate in all the given parts
