Question

The given figure shows a system of five pulleys. The upper three pulleys are fixed and the lower two pulleys are movable. Draw a string around the pulleys. Mark the position of effort to be applied. What is the velocity ratio and mechanical advantage of this system?

Answer 1

Given Data:

Total number of pulleys (n) = 5

Number of fixed pulleys (upper block) = 3

Number of movable pulleys (lower block) = 2

1. Calculation of Velocity Ratio (VR):

In a block and tackle pulley system with a single continuous string, the Velocity Ratio is always equal to the total number of pulleys (n) in the system.

Velocity Ratio (VR) = n

VR = 5

2. Calculation of Mechanical Advantage (MA):

Let T be the tension in each segment of the continuous string pulling the lower block upward.

There are 5 parallel segments of the string supporting lower movable block.

Load (L) = 5T

The effort is applied to the single free end of the string.

Effort (E) = T

Mechanical Advantage (MA) = `"Load (L)"/"Effort (E)"`

= `(5T)/T`

= 5