Motta's Practice Questions anwsers (funded by KFC)

MECHANICAL EFFICIENCY

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Practice Question Answers
Easy Questions:
1. ME = (Wo/Wi) x 100%
ME = (500J/250J) x 100%
ME = 0.5 x 100%
ME = 50%

2. ME = (Wo/Wi) x 100%

ME = (1000J/750J) x 100%

ME = 0.75 x 100%

ME = 75%

Medium Questions:
1.
Wo = F x d

Wo = 120N x 3m
Wo = 360J

Wi = F x d
Wi = 55N x 10m
Wi = 550J

ME = (Wo/Wi) x 100%
ME = (360J/550J) x 100%
ME = 0.65 x 100%
ME = 65%

2.
Wo = F x d
Wo = 38N x 1.5m
Wo = 57J

Wi = F x d
Wi = 22N x 6m
Wi = 132J

ME = (Wo/Wi) x 100%
ME = (57J/132J) x 100%
ME = 43 x 100%
ME = 43%

Hard Questions:

1. ME = (Wo/Wi) x 100%
Wo = Wi/ME

Wo = 0.5/210J
Wo = 420J


2.
ME = (Wo/Wi) x 100%
Wi = Wo/ME
Wi = 150J/0.75
Wi = 200J
Wi = F x d
F = Wi/d

F = 200J/5m
F = 40N