Question

A block and tackle system is used to lift a load having four number of pulleys. It lifts a load of 350 kgf through a vertical height of 20 m.The effort applied is equal to 150 kgf.
(i) Draw a diagram of the system.
(ii) Calculate work done by the effort.
(iii)Calculate efficiency of the system​

Answer 1

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Answer 2

Explanation:

Given A block and tackle system is used to lift a load having four number of pulleys. It lifts a load of 350 kgf through a vertical height of 20 m. The effort applied is equal to 150 kgf.

• Displacement due to the effort VR = 4
• Load L = 350 kgf
• Effort E = 150 kgf
• Displacement due to load dL = 20 m
• So VR = dE / dL
• So dE = VR x dL
•          = 4 x 20
•          = 80 m
• Distance moved by the effort will be 80 m
• Now work done by the effort will be
•            W = Force(effort) x dE
•                 = 150 x 80
•             W = 12,000 J
• So Efficiency of the pulley is the ratio of work output to the work input.
•             Efficiency = Work done by load / Work done by effort
• Now work done by load = Force x dL
•                                       = 350 x 20
•                                      = 7000 kgf
• Therefore efficiency = 7000 / 12,000 x 100
•                                   = 58.33 %

Reference link will be

https://brainly.in/question/14691461