Question

The efficiency of a screw jack increases with a/an . A. decrease in the load B. increase in the load C. decrease in the pitch D. increase in the pitch

Answer 1

Answer:

D

Step-by-step explanation:

I hope answer should be correct

Answer 2

Answer:

Option D

The performance of a screw jack will increase with a boom inside the pitch.

Explanation:

Screw jack:

• Screw jack is a system used to elevate or decrease the burden with the use of screwing mechanism.
• There are two types of jack.
• They are hydraulic and mechanical.
• Hydraulic jacks makes use of cylinder and piston mechanism.
• The motion of piston rod is to elevate or decrease the load.
• Mechanical jacks are hand operated or energy driven.
• Maximum performance of screw jack is

                  $\eta=\left(1-\sin\phi\right)/\left(1+\sin\phi\right)$

• Maximum  performance of screw jack while helix angle is α

                   $\alpha =45^{\circ}-\Phi /2$

• The increase in pitch of the screw promotes the condition of self locking and hence increasing efficiency of screw jack