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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.
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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
Differentiate between a single fixed pulley and a single movable pulley.
Define the following term in reference to a gear system of Driving gear ?
What should be the gear ration of a car : equal to 1, less than 1 or greater than 1, while ascending a hill ?
In a gear system, the gear ration of the driving wheel A and driven wheel B is 10:1. To rotate the driven wheel B in the direction of driving wheel A, the driving wheel A is engaged with other wheel C. what should be the gear ratio of the wheels A and C?
The diagram below shows a pulley arrangement.
- Name the pulleys A and B.
- In the diagram, mark the direction of tension on each strand of string.
- What is the purpose of the pulley B?
- If the tension is T, deduce the relation between
- T and E, and
- E and L.
- What is the velocity ratio of the arrangement?
- Assuming that the efficiency of the system is 100%, what is the mechanical advantage?
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.
What is a pulley?
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?
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)
