Physics problem

Question

A) Eric is pushing a lever to lift a 20kg box which lies a distance of .5 meters from the fulcrum. Eric pushes down on the lever with 50N of force, what distance is Eric from the fulcrum?

 

B) what is the IMA of the lever? What does this number mean?

 

C) what is the AMA of the lever if Erin actually pushes down on the lever with a force of 75N? What does this number mean?

Answer 1

A)

F_E.S_E=F_R.S_R

50 x S_E=20 x 9.8 x0.5

=>  S_E=1.96 m  (at least)

B)

IMA=S_E/S_R=1.96/.5=3.92 This means ideally the lever is going to increase your force 3.92 times.

AMA=F_R/F_E= (20 x 9.8)/75=2.613 This means the lever actually increases your force only 2.613 times (probably due to some friction)