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प्रश्न
Give a reason for the following:
In a single fixed pulley, the velocity ratio is always more than the mechanical advantage.
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उत्तर
In a single fixed pulley, some effort is wasted in overcoming friction between the strings and the grooves of the pulley; so the effort needed is greater than the load and hence the mechanical advantage is less than the velocity ratio.
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.
Fill in the blank:
A pulley is used to change ........................
What is the justification for using the pulley then ?
Name a machine to change the direction of force ?
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 ?
The diagram below shows a pulley arrangement :
(i) Copy the diagram and mark the direction of tension on each strand of the string.
(ii) What is the velocity ratio of the arrangement ?
(iii) If the tension acting on the string is T, then what is the relationship between T and effort E ?
(iv) If the free end of the string moves through distance x, find the distance by which the load is raised.
A type of single pulley is very often used as a machine even though it does not give any gain in mechanical advantage. For what purpose is such a pulley used?
What is a pulley?
A man raises a load of 360 kgf using a block and tackle system of 3 pulleys. If the efficiency of the pulley system is 60%, what effort is applied by the man?
If the weight of the movable pulley is W, obtain the expression for MA, VR, and efficiency.
