Question 5: Two wave pulses are traveling in opposite directions, completely cancel each other as they pass. What happens to the energy possessed by the waves?
When two anti-phase waves moving in opposite direction along the same line meet one another, they cancel one another. However, the energy remains conserved. At the point of superposition, the net displacement of the particles of the medium is zero; which means the potential energy component of the total energy becomes zero. When they pass one another, they continue to move in their own respective directions without any change in their amplitude or speed.