JAMB - Physics (2000 - No. 3)
The velocity ratio of a machine is 5 and its efficiency is 75%. What effort would be needed to lift a load of 150N with the machine?
20N
30N
40N
50N
Explanation
Efficiency = \(\frac{\text{M.A}}{\text{V.R}}\)
75% = \(\frac{\text{M.A}}{\text{V.R}}\)
\(\frac{75}{100} = \frac{\text{M.A}}{5}\)
M.A = \(\frac{75(5)}{100}\) = 3.75
But M.A = \(\frac{\text{Load}}{\text{Effort}}\)
3.75 = \(\frac{150}{\text{Effort}}\)
Effort = \(\frac{150}{3.75}\)
Effort = 40N
75% = \(\frac{\text{M.A}}{\text{V.R}}\)
\(\frac{75}{100} = \frac{\text{M.A}}{5}\)
M.A = \(\frac{75(5)}{100}\) = 3.75
But M.A = \(\frac{\text{Load}}{\text{Effort}}\)
3.75 = \(\frac{150}{\text{Effort}}\)
Effort = \(\frac{150}{3.75}\)
Effort = 40N
Comments (0)
