Just screenshot and mark the answer and then just answer the question ASAP pla

The diagram shows four locations in the electric field of a positive point charge m. at which location is the electric potential the greatest.

If there's a small amount of friction between two surfaces, the result could be select all that applya. no movement b. heatc. a little bit of movementd. sliding around

Ascientist wants to test ways to reduce pollution in lake . what is the bestway of doing this