Physics -Fundamental Concepts
Work, Power and Energy- Its Units and Dimensions
Work and Energy are measured in the same units. Power, being the rate at which work is done, is measured in a different unit
Quantity and Units/Dimensions Work (Energy) Power
Gravitational MKS kg-m Kg-m/sec
FPS ft-lb ft-lb/sec.
CGS gm-cm Gm-cm/sec
Absolute MKS Joule
FPS ft-Poundal ft-poundal/sec
CGS erg Erg/sec.
Different Systems of Units and its conversions
1HP = 746 watt.
1 Joule = 1 Newton 1 m = 105 dyne 102 cm = 107 erg
1 watt = 1 Joule/ sec = 107 erg/sec.
1 cal = 1 calorie = 4.2 Joule
1 MW = 106 watt.
1eV = “e” Joule = 1.6 ´ 10-19 Joule
(e = magnitude of charge on the electron in coulombs)