Welcome to PF, ktlee.
I have a thought that doesn't match the order of the questions, but here it is FWIW.
You have all the information for the coasting part of the motion. You can deduce the friction force from the deceleration, answering question 5 first, then 3,4 and 6. Isn't 2 trivial - it loses all of its energy because it stops.
then would 5 be .4041 m/s^2? or .9526 m/s^2?
The question is no longer showing in the first post and I forget what it was!
Separate names with a comma.