Answer:
35 Joules
Explanation:
Applying
Input Energy(Q) = Useful energy output(U)+Wasted Energy(W)
Q = U+W.............................. Equation 1
Make U the subject of the equation
U = Q-W................... Equation 2
From the question,
Given: Q = 120 Joules, W = 85 Joules
Substitute these values into equation 2
U = 120-85
U = 35 Joules
