Question

In a block and tackle system consisting of 3 pulleys, a load of 75 kgf is raised with an effort of 25 kgf. Find:

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

Answer 1

Load = 75 kgf

Effort = 25 kgf

∴ n = 3

M.A. = `"Load"/"Effort"`

M.A. = `75/25`

M.A. = 3

or MA = n = 3

Velocity ratio VR = n = 3

Efficiency η = `"M.A."/"V.R."= 3/3` = 1 or 100%