Physics P1 help

[ashhadazam]

There is this question.. June 2008 p1 Q.16 . I got the right answer but then i got confused. I know it is something to do with Fs but how do we know whether the the Potential energy is increasing or decreasing ?? Any help would be appreciated


P.S: Best of luck to all of you for Physics P1

 

[ashhadazam]

help me please ?

 

[MAVtKnmJ]

Ep or Potential Energy always increases with increase in height and decreases with decrease in height. Do you understand?

 

[ashhadazam]

I dont think you saw the question.. I knw how potential energy increases or decreases.. But the question talks abt the potential energy of a charge. how are we supposed to know whether the positive plate is at the top or negativeone.. cuz that wud bring a change in answer !

 

[MAVtKnmJ]

Without looking at the question I'll try to answer this.

A charge used in experiments is usually negatively charged or neutral, so if it's being attracted that means it is negatively charged and will be attracted towards the positively charged plate and vice versa!

 

[Perish007]

Charge 'X' is positive. This means it will move in the direction of the electric field if let loose. If it would have been a negative charge it had moved in opposite direction to electric field. Thus, if that +ve charge is moved in the direction of electric feild, it will lose potential energy. In this case by Fs. If it were a -ve charge it would have gained potential energy by Fs.

 

[ashhadazam]

Thnx a lot man !!