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प्रश्न
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?
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उत्तर
- Pulley A is a movable pulley.
Pulley B is a fixed pulley. - Tension T is marked in (f)
-
Pulley B's function is to reverse the direction of effort applied, moving it from upward to downward.
- Relation between:
- T and E are E = T.
- Between E and L, is E = `L/2`
- V.R. = `("Distance moved by effort" d_E)/("Distance moved by load" d_L)`
V.R. = `(2d)/d = 2` - M.A. = Efficiency × V.R.
= `100/100 xx 2 = 2`
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The diagram below shows a pulley arrangement.
(i) In the diagram, mark the direction of the forces due to tension, acting on the pulley P.
(ii) What is the purpose of the pulley Q?
(iii) If the tension is T newton, deduce the relation between T and E.
(iv) Calculate the velocity ratio of the arrangement.
(v) Assuming that the efficiency of the system is 100%, what is the mechanical advantage?
(vi) Calculate the value of E
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.
Name a machine which is used to:
change the direction of force applied.
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Complete the table.
| S. No | Types of Simple Machine | Example |
| 1. | Pulley | |
| 2. | Wheel and axle | |
| 3. | Wedge | |
| 4. | Inclined plan | |
| 5. | Lever | |
| 6. | Screw |
