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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
The mechanical advantage of an actual pulley is less than one. Give a reason. What is the justification for using the pulley then?
Answer the following in short.
Explain the various functions that a machine can perform.
Explain how a gear system can be used to obtain gain in torque? Given one example.
Differentiate between a single fixed pulley and a single movable pulley.
Give reason for the following:
In a single fixed pulley, the velocity ratio is always more than the mechanical advantage.
Give reason for the following:
The lower block of a block and tackle pulley system must be of negligible weight
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
In the alongside the figure of two pulleys shown a system in which one pulley is fixed and the other is movable. What is the velocity ratio of the system?
An effort of 600 N is needed to lift a weight of 1000 N. What are the mechanical advantage and efficiency of the pulley system?
A pulley is a machine made up of a ______.
State one advantage of single movable pulley.
