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प्रश्न
There is no gain in mechanical advantage in the case of a single fixed pulley. Explain, why the pulley is then used?
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उत्तर
It is used only to change the direction of effort to a more convenient direction and to use one’s own weight for the effort.
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 ........................
State two functions of a machine.
Explain how a gear system can be used to obtain gain in torque? Given one example.
Give reason for the following:
In case of a block and tackle arrangement, the mechanical advantage increases with the increase in the number of pulleys.
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.
A type of single pulley is very often used as a machine even though it does not give any gain in mechanical advantage. For what purpose is such a pulley used?
A man raises a load of 360 kgf using a block and tackle system of 3 pulleys. If the efficiency of the pulley system is 60%, what effort is applied by the man?
A pulley system has a velocity ratio of 4 and an efficiency of 90%. Calculate:
(i) the mechanical advantage of the system.
(ii) the effort required to raise a load of 300 N by the system.
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 |
