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प्रश्न
The pulley system shown in the figure is to be used to lift a load W. If the man applying the effort cannot apply a force exceeding 1000 N, what is the maximum load that can be lifted?
The actual load that the man is finally able to lift turns out to be 2700 N. What are the values of the actual M.A., obtained, and the efficiency of the actual set-up?
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उत्तर
The load lifted would be a maximum when conditions are ideal. Since this set-up uses three strands of string, the load gets raised only through 1/3rd of the distance through which the effort moves.
Hence,
Velocity ratio =`("Distance moved by the effort")/("Distance moved by the load")`
`=1/(1//3)=3.`
Under ideal conditions, V.R. = M.A.
Hence, Ideal M.A. of the set-up = 3.
∴ Maximum load that can be lifted = Effort × 3 = 100 N × 3
= 3000 N.
Under actual conditions, M.A. =`"Load"/"Effort"`
=`(2700"N")/(1000"N")`
= 2.7
Efficiency = `"M.A."/"V.R."=2.7/3`
= 0.9 = 90%.
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.
From the diagram given below. answer the question that follows:
1) What kind of pulleys are A and B?
2) State the purpose of pulley B.
3) What effort has to be applied at C just raise the load L = 20 kgf?
(Neglect the weight of pulley A and friction)
State whether the following statement is True or False.
A pulley changes 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 ?
Differentiate between a single fixed pulley and a single movable pulley.
What is a block and tackle system of pulleys?
Give reason for the following:
In case of a block and tackle system, the mechanical advantage increases with the increase in the number of pulleys.
In the case of a block and tackle arrangement, the mechanical advantage increases with the number of pulleys. Explain.
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.
