Lets say i have a horizontal line which is above the x-axis in a 'energy versus time' graph. Since gradient is zero,power is zero. From what i have known,power is the rate at which energy is converted or work is done. If power is zero,no work is done or no energy is converted,then what is the area below the horizontal line? No power is done,means no energy should be used? Second question.If both line have a gentle,upward sloping gradient,power is the same right? But what is one of the line is way up,while another line is just above the x-axis. They both have the same power but the energy dissipated is different.Why is this so??