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प्रश्न
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?
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उत्तर
Given: L = 360 kgf, E = ?, Efficiency = 60% = 0.6,
Velocity ratio = No. of pulley in the system = 3.
Mechanical advantage (M.A.) = V.R. × Efficiency
= 3 × 0.6
= 1.8
But, M.A. =`"Load(L)"/"Effort(E)"`
∴ Effort (E) =`"Load(L)"/"M.A."`
= `360/1.8`
= 200 kgf.
संबंधित प्रश्न
Answer the following in short.
Explain the various functions that a machine can perform.
Name the type of single pulley that can act as a force multiplier. Draw a labelled diagram of the pulley mentioned by you.
Give two reasons why the efficiency of a single movable pulley system is not 100%.
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
The mechanical advantage of an ideal single movable pulley is ______.
Name the type of single pulley that can act as a force multiplier. Draw a labeled diagram of the pulley mentioned by you.
Name a machine which is used to:
change the direction of force applied.
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?
If the weight of the movable pulley is W, obtain the expression for MA, VR, and efficiency.
