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# 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. - ICSE Class 10 - Physics

#### Question

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

1) Distance moved by the effort

2) Work done by the effort

3) M.A. of the pulley system

4) Efficiency of the pulley system

#### Solution

1) Displacement due to the effort is VR = 4

Effort (E)= 50 kgf

VR = d_E/d_L

Effort displacement (dE) =  4 x dL = 4 x 15  = 60 m

Distance moved by the effort is 60 m

2) Work done by the effort is calculated using the following formula.

Work done by effort (WE)= ForceEffort x dE

WE = 50 x 60 = 30000 J

3) Mechanical advantage of the pulley system is calculated as

MA of the pulley system = "Load (L)"/"Effort (E)" = 175/50 = 3.5

4) Efficiency of the pulley is the ratio of work output to the work input required by the system

Efficiency of the pulley system (η) = "Work output (Work Done by Load)"/"Work input (Work Done by Effort)"

Work done by load = ForceLoad x dL = 175 x 15 = 2625 kgf

:. η = 2625/3000 = 0.875 x 100 = 87.5 %

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Solution 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. Concept: Concept of Pulley System.
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