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प्रश्न
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.
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उत्तर
VR = 4, η = 90%
(i) MA = VR × η%
`=(4xx90)/100=3.6`
(ii) MA =`"Load"/"Effort"`
∴ Effort =`"Load"/"MA"`
`=300/3.6`
= 83.33 N
संबंधित प्रश्न
Answer the following in short.
Explain the various functions that a machine can perform.
Explain how a gear system can be used to obtain Change in direction of rotation. Given one example.
Define the following term in reference to a gear system for Gear ratio ?
Define the following term in reference to a gear system for Gain in speed ?
Name the type of single pulley that can act as a force multiplier. Draw a labelled diagram of the pulley mentioned by you.
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.
What is a block and tackle system of pulleys?
(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 pulley system shown in the figure is to be used to lift a load W. If the man applying the effort cannot apply a force exceeding 1000 N, what is the maximum load that can be lifted?
The actual load that the man is finally able to lift turns out to be 2700 N. What are the values of the actual M.A., obtained, and the efficiency of the actual set-up?
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 |
