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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
A boy uses a single fixed pulley to lift a load of 50 kgf to some height. Another boy uses a single movable pulley to lift the same load to the same height. Compare the effort applied by them. Give a reason to support your answer.
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.
Solve the following numerical problem.
What effort will be required to lift a load of 500 N by a single movable pulley? [Hint: Mechanical advantage of a single movable pulley is two].
Name a machine to change the direction of force ?
Explain how a gear system can be used to obtain gain in speed? Given one example.
Define the following term in reference to a gear system for Driven gear ?
Define the following term in reference to a gear system for Gain in speed ?
Define the following term in reference to a gear system for Gain in torque ?
Give reason for the following:
In a single fixed pulley, the velocity ratio is always more than the mechanical advantage.
The mechanical advantage of an ideal single movable pulley is ______.
Name the type of single pulley that can act as a force multiplier. Draw a labeled diagram of the pulley mentioned by you.
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.
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?
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.
Draw a diagram showing a block and tackle system of 4 pulleys.
(i) State, how many strands of tackle support the load?
(ii) Draw arrows to represent tension in each strand.
(iii) Find the mechanical advantage of the system, stating the assumptions made.
(iv) If the load is pulled up by a distance 1m, how much does the effort end move?
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?
