Question

A block and tackle system has the velocity ratio 3. Draw a labelled diagram of the system indicating the points of application and the directions of load L and effort E. A man can exert a pull of 200 kgf. What is the maximum load he can raise with this pulley system is its efficiency is 60%?

Answer 1

E = `L/(n ("number of pulleys"))`

200 = `L/3`

∴ L = 600 kgf

But efficiency = 60 %

= `60/100 xx 600`

= 360

Maximum load that can be raised = 360 kgf