Apoint charge is used to determine the electric field around a charged particle. why is it necessary that the point charge does not affect the position of the charge being tested? a) the amount of charge will increase if the charged particle moves closer to the point charge, so any change in position changes the field. b) the amount of charge will decrease if the charged particle moves closer to the point charge, so any change in position changes the field. c) electric fields are inversely proportional to the square of the distance, so any change in position changes the field. d) electric fields are directly proportional to distance, so any change in position changes the field.

Explanation:

A point charge is used to determine the electric field around a charged particle. The space around a charged particle is called electric field. The direction of electric field is shown by electric field lines. For a point charge it is given by :

Where

k = electrostatic constant

q = point charge

d = distance between charges

It is clear that E is inversely proportional to the square of the distance. Hence, the correct option is (c) "Electric fields are inversely proportional to the square of the distance, so any change in position changes the field".

acceleration = (change in speed) / (time for the change)

change in speed = (20-120)= -100 m/s.

1.5 min = 90 sec

acceleration = -100/90 = -1.11 m/s^2.

we don't care about the 150kg or the 2,500 meters. they don't make any difference.

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