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प्रश्न
Diagram given below shows an arrangement of four pulleys. A load L is attached to the movable lower block and effort E is applied at the free end of the string.
Copy the diagram; and
(i) Draw arrows to indicate tension in each part of the string; and
(ii) Calculate the mechanical advantage of the system.
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उत्तर
The following diagram shows a block and tackle system of 4 pulleys.
(i) The tension in each string is shown by the arrow marked as T.
(ii) If we neglect the friction of the pulleys and weight of the pulleys in the lower block, then
L = 4T and E = T
∴ Mechanical advantage =`"L"/"E"`
=`(4"T")/"T"`
= 4
संबंधित प्रश्न
Differentiate between a single fixed pulley and a single movable pulley.
What is a gear system ?
Define the following term in reference to a gear system for Gain in speed ?
What is a block and tackle system of pulleys?
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?
What is a block and tackle system of pulleys? What precautions would you observe while rounding the string so that the effort is applied in the downward direction?
What is a pulley?
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.
A block and tackle system of pulleys has a velocity ratio of 4.
- Draw a labelled diagram of the system indicating clearly the points of application and directions of load and effort.
- What is the value of the mechanical advantage of the given pulley system if it is an ideal pulley system?
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.
