If Marie pushes horizontally on a table, but not hard enough to get it moving, the friction force acting on the table is A) zero.
B) equal to the weight of the table.
C) equal and opposite to her push.
D) none of the above

It really doesn't matter for any of the questions that you've listed.

Answerthe energy required is 1.60 × 10⁻¹⁸ j, to three significant figures.explanationwe define electric potential as the ratio electric potential energy to the charge,    then the following gives us the potential difference,      the formula  may be on your formula sheet.the change in electric potential energy would be the energy that would needed to move it from point a to point b. solving for that, we get    using q = 8.00  × 10⁻¹⁹ c and  δv = 2.00 v, we get    the energy required is 1.60 × 10⁻¹⁸ j, to three significant figures.