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Easy problem still wrong answer

  • Thread starter melissa_y
  • Start date
17
0
How much work is needed to move a proton from a point with a potential of +630V to a point where it is -60.0V?

Ok so wouldn't I just use the equation:

(Va-Vb)=Wba/q
(-60-630)=Wba/(1.6 x 10^-19)
Wba=-1.104 x 10^-16 J
 

James R

Science Advisor
Homework Helper
Gold Member
600
15
Your equation looks fine to me. What's the answer you expected?
 
17
0
Wba=-1.104 x 10^-16 J

But i keep entering it into the CAPA and it says wrong answer...
 

James R

Science Advisor
Homework Helper
Gold Member
600
15
Try it without the negative sign.

The question is ambiguous, since it doesn't specify who or what is doing the work. If it's the electric field, then the answer is negative. If it's an external force, the answer is positive.
 

Pengwuino

Gold Member
4,854
14
haha i love problems that are so simple yet you dont get an answer. Makes me start pounding on walls. Something simple has obviously gone unnoticed or like someone said, a negative sign is probably missing. Those negative signs piss me off to no end. Everytime i learn something where im told the answer is always positive, i go to church for 40 hours straight to thank god for all the good he has done in the world such as the current subject i was just taught.

I truely hate negatives....
 

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