x(t) = u(t) - u(t-10)
Am I thinking about this correctly... u(t) is 0 from neg. infinity to 0, and 1 after. u(t-10) is the same thing just shifted to the right to "turn on" at 10. So in effect we have a rectangle of amplitude 1 with bounds from 0 to 10. So our integral becomes:
int (1)^2 dt (with bounds of 0 and 10), which = 10?