The following graphs are popular!
Area under force time graph is change in momentum . If area is positive , there is a increase in momentum and negative means decrease in momentum
Area under force displacement graph is work done . If positive work done there could be increase in other forms of energy like kinetic energy or potential energy (gravitational or elastic) and negative means decrease in these other forms of energy and being converted to heat energy.
Area under pressure volume graph is also work done . A increase in volume means work done by gas and decrease in volume means a work done on gas.
Gradient of energy time graph is power. Gradient at a point on the graph gives instantaneous power. Taking the energy /time taken gives average power. Gradient zero at any point in time means instantaneous power zero.
To calculate instantaneous power P=Fv (force and velocity at that instant). Total energy divide by time taken gives average power.
