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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. |
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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
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.
Explain how a gear system can be used to obtain gain in torque? Given one example.
Define the following term in reference to a gear system of Driving gear ?
Define the following term in reference to a gear system for Gain in speed ?
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 block and tackle system of pulleys?
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.
The diagram below shows a pulley arrangement.
(i) In the diagram, mark the direction of the forces due to tension, acting on the pulley P.
(ii) What is the purpose of the pulley Q?
(iii) If the tension is T newton, deduce the relation between T and E.
(iv) Calculate the velocity ratio of the arrangement.
(v) Assuming that the efficiency of the system is 100%, what is the mechanical advantage?
(vi) Calculate the value of E
What is a block and tackle system of pulleys?
Give a reason for the following:
In a single fixed pulley, the velocity ratio is always more than the mechanical advantage.
Give reason for the following:
The efficiency of a pulley is always less than 100%
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.
Draw a diagram of a single fixed pulley and obtain expressions for its:
(i) Mechanical advantage,
(ii) Velocity ratio, and
(iii) Efficiency, in the ideal case.
Diagram given below shows an arrangement of four pulleys. A load L is attached to the movable lower block and effort E is applied at the free end of the string.
Copy the diagram; and
(i) Draw arrows to indicate tension in each part of the string; and
(ii) Calculate the mechanical advantage of the system.
In a single movable pulley system, a load of 125 kgf is lifted by an effort of 75 kgf. Find the percentage efficiency of system.
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.
