For my question about the carton's speed must I do each step you laid out or just the last one? I got the wrong answer. Thanks for your help.

Answer 1

I wish you had checked it step by step, and you would have immediately realized I mixed up the Sin, Cos terms, they are in opposite to what I typed.

Force down plane mgSinTheta, force friction mu*mg*CosTheta.

Duh on me, and duh on you for not working it through and checking.

Answer 2

I worked it through and checked it didn't make sense to me. But I have to finish the assignment soon so I put the answer in anyway. Thanks for you patience.