Test Index

JAMB Physics 2014 Paper

Question : 13

Total: 41

Solution:

Concept:

Efficiency compares the useful work output to the work input, found using mechanical advantage and velocity ratio.

Explanation:

Load,

L = 800 \, \mathrm{N}

Effort,

E = 250 \, \mathrm{N}

Radius of wheel,

R = 800 \, \mathrm{mm}

Radius of axle,

r = 200 \, \mathrm{mm}

Velocity ratio,

VR = \frac{R}{r} = \frac{800}{200} = 4

Mechanical advantage,

MA = \frac{L}{E} = \frac{800}{250} = 3.2

Efficiency,

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

\eta = \frac{3.2}{4} \times 100\%

\eta = 0.8 \times 100\% = 80\%

Answer:

The efficiency of the machine is

80\%

, which corresponds to option B.

Go to Question:

Prev Question

Next Question