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प्रश्न
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.
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उत्तर
(i) It is quite difficult to apply effort in the upward direction if no fixed pulley P2 is used. The fixed pulley changes the direction of effort from upwards to downwards, making the application of the effort more convenient and easier.
(ii) As the movable pulley doubles the effort,
∴ Force, L = 2T
i.e., W = 2T
Mechanical advantage M.A. =`(2"T")/"T"=2`
and V.R. =`("Distance travelled by effort")/("Distance travelled by load")=(2"x")/"x"=2`
The distance travelled by load is half the distance moved by effort = x / 2.
(iii) Since W = 2T or 20 kgf = 2T Here, T = effort
∴ Effort applied =`20/2` = 10 kgf.
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.
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
The pulley system has drawn lifts a load of 150 N when an effort of 60 N is applied. Find its mechanical advantage.
The mechanical advantage of an actual pulley is less than one. Give a reason. What is the justification for using the pulley then?
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.
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 ______.
The diagram below shows a pulley arrangement.
(i) In the diagram, mark the direction of the forces due to tension, acting on the pulley P.
(ii) What is the purpose of the pulley Q?
(iii) If the tension is T newton, deduce the relation between T and E.
(iv) Calculate the velocity ratio of the arrangement.
(v) Assuming that the efficiency of the system is 100%, what is the mechanical advantage?
(vi) Calculate the value of E
Draw the diagram of a single movable pulley and obtain its mechanical advantage, velocity ratio, and efficiency.
Name the type of single pulley that has an ideal mechanical advantage equal to 2. Draw a labelled diagram of the pulley mentioned by you.
