Define the SI unit of energy.
Energy = Force × distance through which point of application of force moves. S.l. unit of energy = SI unit of force × SI unit of distance. = 1 Newton × 1 metre = 1 Nm But 1 N = 1 kg ms-2 ∴ SI unit of energy = 1 kg ms-2 × 1 m = 1 kg m2s-2 The unit of energy is joule (J) Thus 1 Joule (J) = 1 kg m2 s-2.
