1 cal (Int.) = 4.1868 J
= 4.1868 Nm = 4.1868 kg m2/s2
This was historically defined as the heat transfer needed to bring 1 g of liquid water from 14.5°C to 15.5°C, notice the value of the heat capacity of water
1 N-m = 1 J or Force times displacement = energy = Joule
