Answer:
a) 4
b) 12ft
Step-by-step explanation:
a) Mechanical Advantage is defined as the ratio of the load to the effort applied to an object. Mechanical advantage occurs when we can use a minimal effort to overcome a much larger load.
Mathematically; Mechanical advantage = Load/ Effort
Load = 400 lb car engine
Effort applied = Tension generated by the hand crank in the rope = 100lb
Mechanical Advantage = 400lb/100lb
MA = 4
b) Assuming the efficiency is 100%
Efficiency = Workdone by the machine/Work put in the machine * 100%
Workdone by the machine = work output = Force * distance moved by load
= 400*3
= 1200lbft
Work put in the machine = Work input = Force * distance moved by effort
Work input = 100*d
substituting into the equation;
100% = 1200/100d * 100%
1 = 1200/100d
100d = 1200
d = 1200/100
d = 12ft
The length of the rope required to complete the work is 12ft