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प्रश्न
Draw a diagram showing a block and tackle system of 4 pulleys.
(i) State, how many strands of tackle support the load?
(ii) Draw arrows to represent tension in each strand.
(iii) Find the mechanical advantage of the system, stating the assumptions made.
(iv) If the load is pulled up by a distance 1m, how much does the effort end move?
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उत्तर
The adjacent diagram shows a block and tackle system of 4 pulleys.
(i) Four strands of tackle support the load.
(ii) The tension in each strand is shown by the arrow marked as T.
(iii) If we neglect the friction of the pulleys and weight of the pulleys in the lower block, then:
L = 4T
and E = T
∴ M.A. =`"L"/"E"`
= `(4"T")/"T"`
= 4.
(iv) If the load is pulled up by a distance 1m, the effort end moves by 4 m.
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संबंधित प्रश्न
A pulley system with VR = 4 is used to lift a load of 175 kgf through a vertical height of 15 m. The effort required is 50 kgf in the downward direction. (g = 10 N kg-1)
Calculate:
- Distance moved by the effort
- Work done by the effort
- M.A. of the pulley system
- Efficiency of the pulley system
Differentiate between a single fixed pulley and a single movable pulley.
Define the following term in reference to a gear system of Driving gear ?
Name the type of single pulley that can act as a force multiplier. Draw a labelled diagram of the pulley mentioned by you.
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 a reason for the following:
In a single fixed pulley, the velocity ratio is always more than the mechanical advantage.
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.
In a single movable pulley system, a load of 125 kgf is lifted by an effort of 75 kgf. Find the percentage efficiency of system.
A man raises a load of 360 kgf using a block and tackle system of 3 pulleys. If the efficiency of the pulley system is 60%, what effort is applied by the man?
