The motion is described by the Newton's third law.
- According to the first statement, it states that there is equal and opposite reaction. That is the cause and its effect.
- When the blocks are knocked down which means there is transfer of energy and momentum in the two body
- These are described as the conservation of the energy and momentum before and after it remain same.
- In the second statement, there is fall of blocks which shows that here the conservation of momentum does not take place.
- Because the first block has more energy than the second block.