The electrodes of a parallel plate capacitor are squares of side 25 cm, separated by 1.5 mm. the gap is filled with a dielectric material of relative permittivity 6.8. what is the plate charge when the potential difference between the plates is 140 v?

Explanation:

The side of the square = 25 cm =0.25 m

Area of square

Separation between the plate d = 1.5 mm

Relative permitivity k =6.8

The capacitance of the parallel plate capacitor is given by

Voltage across the capacitor V =140 Volt

So charge Q = CV

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.