The power supplied by a certain battery is constant 6 W over the first 5 mins, zero for the following two minutes, a value that increases linearly from zero to 20 W during the next 10 minutes, and a power that linearly decreases 20 W to zero in the following 7 minutes. What is the total energy in joules expended during this 24-minute interval? P.S I know we have to solve for the area under the curve. We will be using E= W*T but i get lost where the value increases from zero to 20W and decreases back from 20W to zero. Any help will be appreciated.