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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
Fill in the blank:
A pulley is used to change ........................
What is a pulley?
What should be the gear ration of a car : equal to 1, less than 1 or greater than 1, while gaining speed on the road ?
What should be the gear ration of a car : equal to 1, less than 1 or greater than 1, while ascending a hill ?
In which direction does the force need to applied, when a single pulley is used with a mechanical advantage greater than one? How can you change the direction of force applied without altering its mechanical advantage? Draw a labelled diagram of the system.
Name a machine which is used to:
change the direction of force applied.
Draw the diagram of a single movable pulley and obtain its mechanical advantage, velocity ratio, and efficiency.
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.
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?
_______ is a machine made up of wheel and rope.
