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प्रश्न
What is a block and tackle system of pulleys?
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उत्तर
A block and tackle system of pulleys consists of two blocks of pulleys, each block having one or more than one pulley. The upper block of pulleys is fixed to a rigid support and the lower block of pulleys is movable. The number of pulleys in the movable block is either equal to or one less than the number of pulleys in the fixed block.
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संबंधित प्रश्न
Fill in the blank:
A pulley is used to change ........................
State two functions of a machine.
Name a machine to change the direction of force ?
Explain how a gear system can be used to obtain Change in direction of rotation. Given one example.
Define the following term in reference to a gear system for Driven gear ?
Give a reason for the following:
In a single fixed pulley, the velocity ratio is always more than the mechanical advantage.
Give reason for the following:
The efficiency of a pulley is always less than 100%
Name a machine which is used to:
change the direction of force applied.
In the case of a block and tackle arrangement, the mechanical advantage increases with the number of pulleys. Explain.
Diagram given below shows an arrangement of four pulleys. A load L is attached to the movable lower block and effort E is applied at the free end of the string.
Copy the diagram; and
(i) Draw arrows to indicate tension in each part of the string; and
(ii) Calculate the mechanical advantage of the system.
