dynamite liberates about 5.4e6 J/kg when it explodes. what fraction of its total energy content is this?

Answer 1

Using E = mc^2, we find that the total energy content of 1 kg of dynamite is:

E = (1 kg)(3.00e8 m/s)^2 = 9.00e16 J

So 5.4e6 J / 9.00e16 J = 6e-11, or about 6 one-hundred-billionths

Answer 2

If you use E=mc^2 for 1 kg you get 9x10^16 Joules = 9 x 10^6 MJ so :

5.4 MJ/9 x 10^6 MJ ~ 6 x 10^-7