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प्रश्न
If the weight of the movable pulley is W, obtain the expression for MA, VR, and efficiency.
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उत्तर
If the weight of the movable pulley with its frame is W, in equilibrium
E = T
L + W = 2T
Or L + W = 2E
⇒ L = 2E − W
MA =`"L"/"E"=("2E"-"W")/"E"=2-"W"/"E"`
VR will remain same, h = `"MA"/"VR"`
`=(2-"W"/"E")/2=1-"W"/(2"E")`
If W << 2E, then 2E = L
Or h = `(1-"W"/"L").`
संबंधित प्रश्न
Select the correct alternative:
A pulley is used because of it
What is a pulley?
What is a gear system ?
Explain the working of a gear system.
What should be the gear ration of a car : equal to 1, less than 1 or greater than 1, while gaining speed on the road ?
The mechanical advantage of an ideal single movable pulley is ______.
A pulley system has a velocity ratio 3. Draw a diagram showing the point of application and direction of load (L), effort (E) and tension (T). It lifts a load of 150 N by an effort of 60 N. Calculate its mechanical advantage. Is the pulley system ideal? Give reason.
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.
Fig shown a block and tackles system of pulleys used to lift a load.
(i) How many strands of tackle are supporting the load?
(ii) Draw arrows to represent tension in each stand.
(iii) What is the mechanical advantage of the system?
(iv) When load is pulled up by a distance 1 m how far does the effort end move?
