A wheel and an axle is used to raise a load whose weight is 800N...

JAMB 2014

A wheel and an axle is used to raise a load whose weight is 800N when an effort of 250N is applied. If the radii of the wheel and axle are 800mm and 200mm respectively, the efficiency of the machine is

A. 90%
B. 80%
C. 85%
D. 87%

WAEC and NECO CBT App for Mobile Devices - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now

Your School's Whatsapp Group - Join Us now

Correct Answer: Option B

Explanation

VR = 800/200 = 4
\(Efficiency = \frac{MA}{VR} \times \frac{100}{1}\)

\(Efficiency = \frac{L}{E} \times \frac{1}{VR} \times \frac{100}{1}\)

\(Efficiency = \frac{800}{250} \times \frac{1}{4} \times \frac{100}{1}\)

= 78.74%
= 80%

There is an explanation video available below.

Previous Next

Go back to Phy classroom

Report an Error Ask A Question Download App