Answer 1.
The main purpose of Thomas Paine's writing The Crisis No. 1 was to encourage undecided American colonists to join the fight against Britain, when many colonists believed they had no chance on winning against one of the greatest and strongest nations.
Answer 2.
Undecided colonists and Tories that were willing to convert to Whigs were the members of his target audience; he wanted to persuade them to join the Patriots, on his essay he stated that Tories (loyalists) were cowards, and that fear was the foundation of toryism, he encouraged American colonists not to fear Britain because they had a chance to win.
Answer 3.
The main opinions Paine expressed were that even though tyranny would not be easy to defeat, it was really possible and that the triumph would be great; that freedom was worth fighting for, and that American patriots had God on their side because their cause was noble and the British' cause was not. Paine expressed the efforts made in the retreat to Delaware, and the advances they had, and his hatred towards Tories.
The Crisis No. 1 was the first of an eighteen series of pamphlets Thomas Paine published during the American Revolution.