Question

A block and tackle system has 5 pulleys. If an effort 0f 1000 N is needed in the downward direction to raise a load of 4500 N, calculate:

1. the mechanical advantage
2. the velocity ratio, and
3. the efficiency of the system.

Answer 1

A block and tackle system has 5 pulleys. (n = 5)

Effort = 1000 N

Load = 4500 N

1. The mechanical advantage M.A = `"𝑙𝑜𝑎𝑑"/"𝑒𝑓𝑓𝑜𝑟𝑡"`= `4500/1000` = 4.5
2. The velocity ratio = n = 5
3. The efficiency of the system η = `"𝑀.𝐴"/"𝑉.𝑅"`= `4.5/5``
   = 0.9 𝑜𝑟 90%