3 physics questions. MUST BE SMART IN PHYSICS.

I need an explanation for this Physics question to help me study.

-attached

Please read the instructions below carefully

For each problem you must:

  • Draw a diagram, (like a free body diagram or a drawing of E-fields)
  • Make a list of knowns and a list of equations
  • Draw a box around your final answer(s)
  • Include Units and pay attention to your significant figures.
  • Show your work.(i.e. write down equation before plugging in numbers, write notes explaining your step if they are hard to follow)
  • here is an example bellow
  • eg