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प्रश्न
Give reason for the following:
The efficiency of a pulley is always less than 100%
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उत्तर
The two reasons are:
(a) Some effort is wasted and overcoming the friction between the strings and the grooves of the pulley.
(b) Some effort is wasted in lifting up the movable block along with the load.
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संबंधित प्रश्न
A pulley system has three pulleys. A load of 120 N is overcome by applying an effort of 50N. Calculate the Mechanical Advantage and Efficiency of this system.
What is the mechanical advantage of an ideal pulley?
The mechanical advantage of an actual pulley is less than one. Give a reason. What is the justification for using the pulley then?
What is the justification for using the pulley then ?
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].
Give two reasons why the efficiency of a single movable pulley system is not 100%.
What is a block and tackle system of pulleys?
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.
Give a reason for the following:
In a single fixed pulley, the velocity ratio is always more than the mechanical advantage.
_______ is a machine made up of wheel and rope.
