A block and tackle system of pulleys has a Velocity Ratio (VR) = 5. Draw a labelled diagram of the system indicating clearly the direction of tension, load and effort.
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As, in a block and tackle system,
V.R. = total number of pulleys used in both the blocks
So, for V.R. = 5, a total of five pulleys are needed. For the convenience of applying the effort in the downward direction, the upper (fixed) block is given three pulleys and the lower (movable) block is given two pulleys, and one end of the string is tied to the hook of the lower (movable) block.
The labelled diagram of the system is shown below :
Here, the load L is attached to the hook of the lower movable block and the effort E is applied at the free end of the string in the downward direction. The tension T is the same all along the string, and the load is supported by the tension in the five segments of the string, so
L = 5T and E = T