It's a bit of a trick question, had the same one on my homework. You're given an electric field strength (1*10^5 N/C for mine), a drag force (7.25*10^-11 N) and the critical info is that it's moving with constant velocity(the particle is in equilibrium/not accelerating).
<span>All you need is F=(K*Q1*Q2)/r^2 </span>
<span>Just set F=the drag force and the electric field strength is (K*Q2)/r^2, plugging those values in gives you </span>
<span>(7.25*10^-11 N) = (1*10^5 N/C)*Q1 ---> Q1 = 7.25*10^-16 C </span>
Temperature and rate of evaporation are proportional to each other. Surface area: As the surface area increases, the rate of evaporation increases. The surface area and rate of evaporation are proportional to each other. Humidity: The rate of evaporation decreases with an increase in humidity.
True because friction happens when two things are rubbed against each other and it creates force and sliding something vigorously against something else can create force.