6. three charged particles make up an equilateral triangle of side length a. the two particles at the base have a charge q, and the particle at the apex has a charge 2q. (a) find the field in the center of the triangle (a point equidistant from each vertex), in terms of q and a. (b) when you place a charge {q}' along the baseline, halfway between the two particles with charge q, the electric field in the center of the triangle is zero. what is the value of {q}' ?

Amira pulls a 3 pound wagon 4 feet. how much work has she done?

Because air contracts as it cools, the air pressure inside a freezer is typically lower than on the outside. why do ice cubes inside a freezer tend to shrink over time? a. the ice dissolves oxygen from the air, forming a denser crystalline matrix.b. the ice reacts chemically with carbon dioxide in the air, forming gaseous carbon compounds.c. the ice melts, and then the liquid freezes as ice crystals on the bottom of the freezer.d. the ice sublimes, and then the water vapor deposits as ice crystals on the sides of the freezer.

Aparticle's position is given by x = 3.00 - 9.00t + 3t2, in which x is in meters and t is in seconds. (a) what is its velocity at t = 1 s? (b) is it moving in the positive or negative direction of x just then? (c) what is its speed just then? (d) is the speed increasing or decreasing just then? (try answering the next two questions without further calculation.) (e) is there ever an instant when the velocity is zero? if so, give the time t; if not, answer "0". (f) is there a time after t = 3 s when the particle is moving in the negative direction of x? if so, give the time t; if not, answer "0".