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प्रश्न
Select the correct alternative:
A pulley is used because of it
विकल्प
has the mechanical advantage greater than one
has 100% efficiency
helps to apply the force in a convenient direction
requires more effort to raise a less load.
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उत्तर
helps to apply the force in a convenient direction
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संबंधित 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.
The pulley system has drawn lifts a load of 150 N when an effort of 60 N is applied. Find its mechanical advantage.
State two functions of a machine.
The mechanical advantage of an actual pulley is less than one. Give a reason. What is the justification for using the pulley then?
Explain how a gear system can be used to obtain gain in speed? Given one example.
What should be the gear ration of a car : equal to 1, less than 1 or greater than 1, while ascending a hill ?
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?
The diagram below shows a pulley arrangement :
(i) Copy the diagram and mark the direction of tension on each strand of the string.
(ii) What is the velocity ratio of the arrangement ?
(iii) If the tension acting on the string is T, then what is the relationship between T and effort E ?
(iv) If the free end of the string moves through distance x, find the distance by which the load is raised.
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.
