The diagram shown represents a block-and-tackle pulley system on which an effort of W Newtons supports a load of 120.0N. If the efficiency of the machine is...

Assessment: JAMB UTME - Physics - 2018 Subject: Physics

Question 1 Report

The diagram shown represents a block-and-tackle pulley system on which an effort of W Newtons supports a load of 120.0N. If the efficiency of the machine is 40, then the value of W is?

28.0

48.0N

233.0N

50.0N

Answer Details

Let the total number of pulleys used in both the blocks be

n

.
In a block-and-tackle pulley system, the velocity ratio is equal to n.
Efficiency =

\frac{MA}{VR} \times 100 %

MA = \frac{L}{E}, VR = n

Efficiency =

\frac{L}{E} \times \frac{1}{n} \times 100 %

E = \frac{L}{Eff. \times n} \times 100 %

E = \frac{120 N}{40 % \times 6} \times 100 %

E = 50 N

Read lesson note on Simple Machines (JAMB)

Simple Machines

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The diagram shown represents a block-and-tackle pulley system on which an effort of W Newtons supports a load of 120.0N. If the efficiency of the machine is...

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