Question

Given that the relations between the fundamental units of mass, length, time, in the FPS (feet, pound, second) system, and the MKS (metre, kilogram, second) system, are 

1 pound = 0.4536 kg 

1 feet = 0.5045 metre 

1 second = 1 second, 

find the relation, between the units of energy (foot poundal in FPS system, and joule in the MKS system).

Answer 1

We have, 

[Energy] = [ML2T –2] 

∴ The units of energy, in the FPS, system, 

Foot poundal = (pound) (foot)² (second)^-2 

Similarly, the unit of energy, in the MKS system, 

joule = (kilogram) (metre)² (second)^-2

Thus 1 foot poundal = 0.1255 joule