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प्रश्न
What is the relation between the mechanical advantage and the number of strands of string used to support the load, in a ‘block and tackle’ set-up?
उत्तर
The mechanical advantage is equal to the number of strands of string, used to support the load, only if the ‘block and tackle set up’ can be assumed to be ideal (absence of friction, etc.) and the lower blocks of pulleys have negligible weight. Both these conditions cannot be satisfied in actual practice. Hence, in practical situations, the M.A. of a ‘block and tackle set up’ is always less than the fire number of strands of string used to support the load.
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संबंधित प्रश्न
Select the correct alternative:
A pulley is used because of it
State if the following statement is true or false. Correct the statement if it is false.
A single movable pulley is a pulley that has its axis of rotation fixed.
Name a machine to change the direction of force ?
What is a gear system ?
Define the following term in reference to a gear system for Gain in torque ?
The diagram below shows an arrangement of three pulleys A, B, and C. The load is marked as L and the effort as E.
- Name the Pulleys A, B, and C.
- Mark in the diagram the directions of load (L), effort (E) and tension T1 and T2 in the two strings.
- How are the magnitudes of L and E related to the tension T1?
- Calculate the mechanical advantage and velocity ratio of the arrangement.
- What assumptions have you made in parts (c) and (d)?
Give reason for the following:
The lower block of a block and tackle pulley system must be of negligible weight
Give a reason for the following:
In a single fixed pulley, the velocity ratio is always more than the mechanical advantage.
A pulley is a machine made up of a ______.
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.
