Physics/math

how do i derive "f"?
me

Two identical small charged spheres are a certain distance apart, and each one initially experiences an electrostatic force of magnitude f due to the other. with time, charge gradually leaks off of both spheres. when each of the spheres has lost half its initial charge, the magnitude of the electrostatic force will be

Which is the best for showing percentages of different types of cars sold(gas hybrid , electric , other ) in the united states ?

You are a sales representative for a company that makes a new alternate fuel for vehicles. you have prepared a presentation for the environmental engineers to sell your new product. what question do you expect the audience to ask regarding whether the new fuel will cause less damage to the environment? a. do we have to change any parts of the vehicle to use this alternate fuel? b. will the vehicles get better fuel mileage with the alternate fuel? c. how much greenhouse gas does your fuel produce compared with current fuel sources? d. is the alternate fuel more expensive than fossil fuel?