Engineering Homework Help

Hello, I do have a practice quiz question that I got 5 of 7 in the first problem and 6 of 7 for the second problem and and 4.5 for the third problem points and I have the correct solutions for all the questions. I just want to find out my mistake and provide explanation for the correct answers. Please see the instructions file.

Also, i want a similar problem “Practice Question” from the worksheets attached and provide explanation for each step.