Solve step by step and explain all work.

Arresto-momentum is a spell used to \"slow or stop the target's velocity\". If 68 kg wand-less Harry Potter falls from 100 m above Earth. Because his mouth is full of his favorite bacon sandwich (not the detestable corned beef!), Ron waits until Harry is 5 m from the ground to use this spell to fully arrest his momentum just before Harry touches the unforgiving stone of the Hogwarts courtyard. a) Low: what is Harry's momentum when the spell is cast (when he is 5m above the ground)? b) Med: what is the impulse Harry receives from the spell, which undoubtedly saves his life? c) High: how many g's does Harry experience during the arresting portion of his fall