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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
A pulley system with VR = 4 is used to lift a load of 175 kgf through a vertical height of 15 m. The effort required is 50 kgf in the downward direction. (g = 10 N kg-1)
Calculate:
- Distance moved by the effort
- Work done by the effort
- M.A. of the pulley system
- Efficiency of the pulley system
Solve the following numerical problem.
What effort will be required to lift a load of 500 N by a single movable pulley? [Hint: Mechanical advantage of a single movable pulley is two].
Name a machine to change the direction of force ?
Differentiate between a single fixed pulley and a single movable pulley.
Give reason for the following:
In case of a block and tackle arrangement, the mechanical advantage increases with the increase in the number of pulleys.
The mechanical advantage of an ideal single movable pulley is ______.
Give reason for the following:
The efficiency of a pulley is always less than 100%
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.
State one advantage of single movable pulley.
| Meera chose to use a block and tackle system of '9' pulleys instead of a single movable pulley to lift a heavy load. |
Why should she connect more number of pulleys in the upper fixed block?
