Nuclear fusion reactions require a large initial input of energy in order to proceed. This energy is required to overcome:
electron attraction
proton attraction
electron repulsion
proton repulsion

Question

Nuclear fusion reactions require a large initial input of energy in order to proceed. This energy is required to overcome: 
    electron attraction 
   proton attraction 
   electron repulsion 
   proton repulsion

.sam. · Answer

Its related to Coulomb Barrier for Fusion
usually to overcome the the electric repulsion to get close enough for the attractive nuclear strong force to take over to fuse the particles

.sam. · Answer

proton repulsion

anonymous · Answer

Oh, okay thank you, one more thing if you don't mind. Can you explain how I would get to the answer of this question. In a nuclear reaction, 2.50 x 1012 joules of energy have been released. What does this value equate to in kilograms?
(1 J = 1 kg m2/s2) I have multiple questions like this.