A machine is used to lift a load of 20 N through a height...
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
Correct answer is B
Efficiency = work outputwork input×1001
= 40 = 20×10x×1001
= 500J