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प्रश्न
A block and tackle system has V.R. = 5.
Rohan exerts a pull of 150 kgf. What is the maximum load he can raise with this pulley system if its efficiency = 75%?
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उत्तर
Given: Velocity ratio, VR = 5
Effort = 150 kgf
Efficiency = 75%
We know that efficiency, `eta = "Mechanical Advantage"/"Velocity Ratio"`
`75/100 = "MA"/5`
`Ma = 5 xx 75/100`
∴ Mechanical advantage = 3.75
But, Mechanical advantage = `"Load(L)"/"Effort(E)"`
∴ Load = Mechanical advantage x Effort
= 3.75 × 150 Kgf
= 562.5 Kgf
Therefore, Rohan can raise a maximum load of 562.5 kgf with this pulley system.
संबंधित प्रश्न
What is the justification for using the pulley then ?
Differentiate between a single fixed pulley and a single movable pulley.
Give reason for the following:
The lower block of a block and tackle pulley system must be of negligible weight
Give reason for the following:
The efficiency of a pulley is always less than 100%
Write two uses of pulleys. Is pulley a force multiplier?
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.
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 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?
| Meera chose to use a block and tackle system of '9' pulleys instead of a single movable pulley to lift a heavy load. |
Why should she connect more number of pulleys in the upper fixed block?
