What is negative potential? What is negative potential? Also what happens to the total energy and kinetic energy in case of negative potential energy?
 A: Negative potential is just a potential that has attractive nature.               
If you see Earth's potential, it is negative as it is attractive.                
If you study potential of electrons in atom, you will find it to be negative. The positively charged nucleus attracts the negatively charged electrons. The negative potential energy for H-atom is -13.6 eV. This implies that if you provide additional 13.6 eV energy to the electron, then it will become a free electron.  
Also in quantum mechanics, we use negative potentials to indicate its attractive nature.                                                                       
The total energy remains positive and so does the kinetic energy. Kinetic energy can never be negative as that would imply velocity to be a complex number, which is not the reality.                                                            
If you study the energies of satellites of Earth, you will see potential energy is negative but total and kinetic energies are positive.                      
Now the following comments may confuse you if you are not familiar with quantum mechanics. So you may ignore this. In QM, there are often cases when a particle can overcome a potential barrier that is higher than its total energy. That seems to indicate that its, kinetic energy is negative but that really is not the case. It is a probabilistic theory.
