A machine has a velocity ratio of 6 and an efficiency of 75%. Calculate the effort needed to raise a load of 90N

if it were perfect Fperfect = 90/6 = 15 N

so
0.75 F = 15 N
F = 20 Newtons

20N

22

V.R=6; Eff=75%; L=90N E= ?

Eff=M.A/V.R ˟ 100
75/100=M.A/6
100M.A=450
Divide by 100
M.A=4.5
M.A=L/E
4.5=90/E
4.5E=90
Divide both sides by 4.5
E=90/4.5
E=20N

20N

20N

Correct! The effort needed to raise the load of 90N with a velocity ratio of 6 and an efficiency of 75% is 20N.