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प्रश्न
Select the correct alternative:
A pulley is used because of it
पर्याय
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
Rohan exerts a pull of 150 kgf. What is the maximum load he can raise with this pulley system if its efficiency = 75%?
Define the following term in reference to a gear system of Driving gear ?
Define the following term in reference to a gear system for Gear ratio ?
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.
Write two uses of pulleys. Is pulley a force multiplier?
(a) Fig represents an incomplete diagram of a simple string pulley system. Copy this diagram on a new page and complete it and mark where the effort must be applied to lift the load.
(b) What is the velocity ratio of this system?
(c) If the pulley system is 80% efficient and the load is 720 N, then
(i) What effort must be applied to lift the load?
(ii) What work must be done must be done in lifting the load through a distance of 2 m using this machine?
The alongside figure shows the combination of a movable pulley P1 with a fixed pulley P2 used for lifting up a load W.
(i) State the function of the fixed pulley P2.
(ii) If the free end of the string moves through a distance x, find the distance by which the load W is raised.
(iii) Calculate the force to be applied at C to just raise the load W = 20 kgf, neglecting the weight of the pulley P1 and friction.
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 |
| 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?
Name the type of single pulley that has an ideal mechanical advantage equal to 2. Draw a labelled diagram of the pulley mentioned by you.
