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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
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
Fill in the blank:
A pulley is used to change ........................
Define the following term in reference to a gear system for Driven gear ?
Define the following term in reference to a gear system for Gain in torque ?
Name the type of single pulley that can act as a force multiplier. Draw a labelled diagram of the pulley mentioned by you.
The diagram below shows an arrangement of three pulleys A, B, and C. The load is marked as L and the effort as E.
- Name the Pulleys A, B, and C.
- Mark in the diagram the directions of load (L), effort (E) and tension T1 and T2 in the two strings.
- How are the magnitudes of L and E related to the tension T1?
- Calculate the mechanical advantage and velocity ratio of the arrangement.
- What assumptions have you made in parts (c) and (d)?
Give reason for the following:
The lower block of a block and tackle pulley system must be of negligible weight
What is the use of a fixed pulley?
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.
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.
