The Student Room Group

A2 Physics coulomb's law question help please!

http://postimg.org/image/ke81zgzdt/

I simply use the equation F= kQq/r^2

mg = 0.018N

Construct a triangle to get the Force of the proton, and then substitute the force value into F=kQq/r^2

And I always get the r value something around x10^-14 or something. The answer is supposed to be 0.1x10^-6

I do not use 1.8m for anything, and I feel like I am missing something. Spent like 3 hours on this, help please!!
Hiya! You may be best off posting this in the Physics forum. You can find it here. The reason is that the people who will be able to help you are more likely to check that forum than a more general one with many different topics. Good luck! :smile:
Original post by The Best1
http://postimg.org/image/ke81zgzdt/

I simply use the equation F= kQq/r^2

mg = 0.018N

Construct a triangle to get the Force of the proton, and then substitute the force value into F=kQq/r^2

And I always get the r value something around x10^-14 or something. The answer is supposed to be 0.1x10^-6

I do not use 1.8m for anything, and I feel like I am missing something. Spent like 3 hours on this, help please!!


You need to show your working if you want us to find out where you have gone wrong.
How did you calculate F, exactly?
Have you been careful with units?

Quick Reply