In lab you measured the force between two charged pith balls where the pith balls were of the same size and mass. your assumption was that the charge on the balls was the same. consider this change to that situation. instead of identical pith balls, one has twice the surface area of the other. the pith balls were charged by touching them with a chemical piece of pvc pipe at the same time. (the pith balls touched opposite sides of the pvc when they were charged.) both pith balls hang from strings of length l. assume the masses are the same and both pith balls hang at the same angle. derive an expression for the distance between the pith balls.

magnified images possible images can be real = projected onto a screen

graph slopes whilst gas cools, then it is flat whilst conensation to liquid happens, the coolong liquid then graphs as a slope when it solidifies graph is flat

latent heat

volts times amps 6 x 0.5 3w

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.