JAMB - Physics (2011 - No. 11)
A machine is used to lift a load of 20 N through a height of 10 m. if the efficiency of the machine is 40%, how much work is done?
80 J
500 J
300 J
120 J
解释
Efficiency = \( \frac{\text{work output}}{\text{work input}} \times \frac{100}{1} \)
= 40 = \( \frac{20 \times 10 }{x} \times \frac{100}{1} \)
= 500J
= 40 = \( \frac{20 \times 10 }{x} \times \frac{100}{1} \)
= 500J