how are we supposed to know? you don't give us any information.
Answer:
Dr Hewitt is able to break the piece of wood in his demonstration given that he had knowledge about the concept of momentum, which is esentially the product of the mass and speed of an object.
Aplying this idea, he used the correct momentum of his hand over a short period of time and that is how he was able to break the piece of wood.
They will get thirsty and wither away
