A screw jerk whose pitch is 4 4mm is use to raise a body of mass 800kg through a height - Physics - Machines

Question

A screw jerk whose pitch is 4 4mm is use to raise a body of mass
800kg through a height of 40cm The length of the turning back of
the jerk os 70cm If the efficiency of the jerk is 60% calculate
the:
1 Velocity ratio of the jerk
2 Mechanical advantage of the jerk
3 Effort required in raising the body (g=10m/s, ?=22/7)

Sanat K Mukherjee · Accepted Answer

Dear Student,
Velocity ratio : V R
 = 2πLpitch, where L is the length of the turning bar = 70 cm=0
70mpitch = 4 4 mm = 0 0044 mV R
 = 2×227×0 700 0044=1000
2 Efficiency of the jack = Mechanical advantage (M A )V R
×100
â€‹â€‹60=M A 1000×100M A
=600

3 Mechanical advantage (M A ) is the ratio of the load (L) to the
Effort (E)
M A =LEE=LM A =mgM A =800×10600=403N

Therefore, Effort required in raising the body = 40/3 N

Regards