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प्रश्न
Answer the following in detail.
How does a pulley make work simpler?
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उत्तर
A pulley is a wheel or a circular disc that can rotate freely about its axle. It is used to lift heavy objects. It is neither a force multiplier nor a speed multiplier. It only changes the direction of the applied force from upwards against gravity to downwards towards gravity. There are two types of pulley systems – Single fixed pulley and single movable pulley.
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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.
What is a pulley?
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].
Define the following term in reference to a gear system for Driven 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?
Draw a diagram of a combination of three movable pulleys and one fixed pulley to lift up a load. In the diagram, show the directions of load, effort and tension in each strand. Find:
- mechanical advantage,
- Velocity ratio and
- efficiency of the combination in ideal situation.
What is the use of a fixed pulley?
State two reasons, why the efficiency of a pulley system is not 100 percent?
If the weight of the movable pulley is W, obtain the expression for MA, VR, and efficiency.
