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प्रश्न
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?
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उत्तर
If there are n movable pulleys connected to a fixed pulley, then the velocity ratio is
V.R = 2n
Velocity ratio of the system = 2.
Mechanical Advantage = `"Load"/"Effort"=1000/600`
=`5/3`
Efficiency = `"M.A."/"V.R."`
= `(5//3)/2=5/(3xx2)=5/6`
= 83.3%.
संबंधित प्रश्न
Draw a neat labelled diagram showing a pulley being used to lift a load. How are load and effort related in an ideal situation?
Answer the following in short.
Explain the various functions that a machine can perform.
What is a single movable pulley? What is its mechanical advantage in the ideal case?
Differentiate between a single fixed pulley and a single movable pulley.
Fig shown a block and tackles system of pulleys used to lift a load.
(i) How many strands of tackle are supporting the load?
(ii) Draw arrows to represent tension in each stand.
(iii) What is the mechanical advantage of the system?
(iv) When load is pulled up by a distance 1 m how far does the effort end move?
A type of single pulley is very often used as a machine even though it does not give any gain in mechanical advantage. Name the type of pulley used.
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?
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.
If the weight of the movable pulley is W, obtain the expression for MA, VR, and efficiency.
A boy lifts a load of 40 kgf through a vertical height of 2m in 5s by using a single fixed pulley when he applies an effort of 48 kgf. Calculate:
(i) the mechanical advantage, and
(ii) the efficiency of the pulley. Why is the efficiency of the pulley is not 100%?
(iii) the energy gained by the load in 5s, and
(iv) the power developed by the boy in raising the load.
