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प्रश्न
A block and tackle system of pulleys has a velocity ratio of 4.
- Draw a labelled diagram of the system indicating clearly the direction of the load and effort.
- Calculate the potential energy of the load 100 kgf lifted by this pulley to a height 5 m. (g = 10 ms−2)
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उत्तर
a. Pulley drawn correctly with support.
Correct connection of tackle, Marking load and effort with correct direction and tension.

b. U = mgh
= 100 × 10 × 5
= 5000 J
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संबंधित प्रश्न
A pulley system has three pulleys. A load of 120 N is overcome by applying an effort of 50 N. Calculate the Mechanical Advantage and Efficiency of this system.
Select the correct alternative:
A pulley is used because of it
Differentiate between a single fixed pulley and a single movable pulley.
Explain the working of a gear system.
Define the following term in reference to a gear system for Gear ratio ?
Give reason for the following:
The lower block of a block and tackle pulley system must be of negligible weight
(a) Fig represents an incomplete diagram of a simple string pulley system. Copy this diagram on a new page and complete it and mark where the effort must be applied to lift the load.
(b) What is the velocity ratio of this system?
(c) If the pulley system is 80% efficient and the load is 720 N, then
(i) What effort must be applied to lift the load?
(ii) What work must be done must be done in lifting the load through a distance of 2 m using this machine?

A type of single pulley is very often used as a machine even though it does not give any gain in mechanical advantage. Name the type of pulley used.
Draw the diagram of a single movable pulley and obtain its mechanical advantage, velocity ratio, and efficiency.
Draw a diagram of a single fixed pulley and obtain expressions for its:
(i) Mechanical advantage,
(ii) Velocity ratio, and
(iii) Efficiency, in the ideal case.
