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प्रश्न
Differentiate between a single fixed pulley and a single movable pulley.
State four differences between a single fixed pulley and a single movable pulley.
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उत्तर
| Single fixed pulley | Single movable pulley | |
| 1. | This pulley has a fixed axis of rotation. | The axis of rotation of this pulley is not fixed. |
| 2. | The load is attached to one end of the rope. | The load is attached to the pulley. |
| 3. | Only the direction of the force is changed, not the magnitude. [We can lift the object higher, but the heaviness of load remains the same.] | The direction of the force as well as the magnitude of the force change. |
| 4. | The mechanical advantage of this pulley is 1. | The mechanical advantage of this pulley is 2. |
| 5. | Example: Used to draw water from wells. | Example: Used in construction cranes, Weight lifting, machines in the gym, etc. |
संबंधित प्रश्न
The pulley system has drawn lifts a load of 150 N when an effort of 60 N is applied. Find its mechanical advantage.
State whether the following statement is True or False.
A pulley changes the direction of force.
State if the following statement is true or false. Correct the statement if it is false.
A single movable pulley is a pulley that has its axis of rotation fixed.
What is a gear system ?
Define the following term in reference to a gear system of Driving gear ?
In a gear system, the gear ration of the driving wheel A and driven wheel B is 10:1. To rotate the driven wheel B in the direction of driving wheel A, the driving wheel A is engaged with other wheel C. what should be the gear ratio of the wheels A and C?
What is a single movable pulley? What is its mechanical advantage in the ideal case?
Give two reasons why the efficiency of a single movable pulley system is not 100%.
What is the use of a fixed pulley?
Write two uses of pulleys. Is pulley a force multiplier?
What is a block and tackle system of pulleys?
In the case of a block and tackle arrangement, the mechanical advantage increases with the number of pulleys. Explain.
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?
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.
A ‘block and tackle’ system used 3 pulleys in the lower block and 4 pulleys in the upper block. What is the ‘velocity ratio’ of this system? If the load is to be lifted by a person capable of applying a maximum effort of 1000 N, what is the maximum load than can be lifted under ideal conditions?
The actual maximum load that gets lifted turns out to be 6300 N. What are the values of the actual M.A. and efficiency of the set-up?
A boy lifts a load of 40 kgf through a vertical height of 2m in 5s by using a single fixed pulley when he applies an effort of 48 kgf. Calculate:
(i) the mechanical advantage, and
(ii) the efficiency of the pulley. Why is the efficiency of the pulley is not 100%?
(iii) the energy gained by the load in 5s, and
(iv) the power developed by the boy in raising the load.
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?
