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प्रश्न
A boy uses a single fixed pulley to lift a load of 50 kgf to some height. Another boy uses a single movable pulley to lift the same load to the same height. Compare the effort applied by them. Give a reason to support your answer.
उत्तर
The ratio of load to the effort is called the mechanical advantage.
Mechanical advantage (MA) = `"Load(l)"/"Effort(E)"`
The above equation indicates that 'MA' and 'Effort' are inversely proportional.
The mechanical advantage of the single fixed pulley is 1.
For, single movable pulley = 50 kgf
:. Effort (Esingle fixed pulley) = `"Load"/(MA_"single fixed pulley")`
= `50/1 = 50` kgf
Effort (Esingle fixed pulley) = `"Load"/(MA_"single movable pulley")`
= `50/2 = 25` kgf
Therefore, the boy using a single movable pulley requires lesser effort to lift an equal load of 50 kgf when compared with the effort required by the boy using a single fixed pulley.
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संबंधित प्रश्न
A block and tackle system has V.R. = 5.
Draw a neat labeled diagram of a system indicating the direction of its load and effort
Give two reasons why the efficiency of a single movable pulley system is not 100%.
What is a block and tackle system of pulleys?
Give reason for the following:
The lower block of a block and tackle pulley system must be of negligible weight
Give reason for the following:
In case of a block and tackle system, the mechanical advantage increases with the increase in the number of pulleys.
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.
A block and tackle system of pulleys has a velocity ratio of 4.
- Draw a labelled diagram of the system indicating clearly the points of application and directions of load and effort.
- What is the value of the mechanical advantage of the given pulley system if it is an ideal pulley system?
A pulley system has a velocity ratio of 4 and an efficiency of 90%. Calculate:
(i) the mechanical advantage of the system.
(ii) the effort required to raise a load of 300 N by the system.
_______ is a machine made up of wheel and rope.
| 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?
