Answer:
a. 30%
Explanation:
Given the following data;
Energy as effort, Ee = 20 J
Energy as heat, Eh = 6 J
To find the percentage efficiency (P.E);
P.E = Eh/Ee * 100
Substituting into the formula, we have;
P.E = 6/20 * 100
P.E = 6 * 5
P.E = 30 %
Therefore, the percentage efficiency of the machine is 30 %.
