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प्रश्न
What is a block and tackle system of pulleys?
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उत्तर
A block and tackle system of pulleys consists of two blocks of pulleys, each block having one or more than one pulley. The upper block of pulleys is fixed to a rigid support and the lower block of pulleys is movable. The number of pulleys in the movable block is either equal to or one less than the number of pulleys in the fixed block.
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संबंधित प्रश्न
Define the following term in reference to a gear system for Gain in torque ?
A block and tackle pulley system has a velocity ratio 5. Draw a labelled diagram of this system. In your diagram, indicate clearly the points of application and the directions of the load and effort.
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.
What is a pulley?
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.
A block and tackle system of pulleys has a velocity ratio of 4.
- Draw a labelled diagram of the system indicating clearly the points of application and directions of load and effort.
- What is the value of the mechanical advantage of the given pulley system if it is an ideal pulley 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 |
A block and tackle system of pulleys has a velocity ratio of 4.
- Draw a labelled diagram of the system indicating clearly the direction of the load and effort.
- Calculate the potential energy of the load 100 kgf lifted by this pulley to a height 5 m. (g = 10 ms−2)
