Must two quantities have the same dimensions if you are subtracting them?

Two identical 82 mg dust particles very far apart (pee 0) are moving directly toward each other at a speed of 3698 m/s. the charge on each is-719 ? c. determine how close they will get to each other. let k = 9x109 n-m2/c2 & ignore gravity.

The chemical effect of the endocrine system is longer lasting than the chemical effect of the nervous system. select the best answer from the choices provided t f

If gases like carbon dioxide and methane make up less than 1% of the total atmosphere, why is it important for scientists to monitor changes in percentages of these gases?