1. In Classical Hamiltonian, it's equal to the kinetic energy plus potential energy.. but I read it that for a free particle, it doesn't even depend on position.. i thought the potential energy depends on position. If it doesn't depend on position, what does it depend on? 2. Since the Hamiltonian is equal to the potential energy plus kinetic energy. The Hamiltonian can be measured as when you measured the electric field which is a potential energy. But I read the Hamiltonian can't be observed or measured.. how come? This is an entirely classical question so please do NOT forward this to the QM forum. Thank you.