Why can water dissolve some ionic compounds, like NH4Cl, as well as some nonionic compounds, like methanol?

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.

How much force must a locomotive exert on a 12840-kg boxcar to make it accelerate forward at 0.490 m/s2?

Where is the potential energy throughout the loading, cocking, and releasing of the trebuchet?