What is the net electric field at point P in this physics problem?

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The discussion focuses on calculating the net electric field at point P, located 2 meters to the right of charge Q2, which is 3 meters apart from charge Q1. The charges are Q1 = -14 C and Q2 = +20 C, resulting in calculated electric fields of -5.04 x 10^9 N/C from Q1 and 4.5 x 10^10 N/C from Q2. The final net electric field is approximately 3.996 x 10^10 N/C. Participants emphasize the importance of including the sign of the charges and the direction of the electric field in the final answer. The conversation concludes with encouragement for the test-taker to remember these details for their upcoming exam.
Burger
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Physics Problem , please help I'm writing a test tomorrow and want to know if I'm right.
The Question :

Two point charges Q1 and Q2 are spaced 3m apart.

Q1's charge = 14C
Q2's charge = +20 C

*Q1 -------(3meters)------- *Q2 ----(2meters)---- *P

Calculate the net electric field at point P, 2m right from where Q2 is situated?


My Calculations :

Q1 on P = -5.04 x10^9
Q2 on P = 4.5 x10^10

Final answer = Net : 3.996x10^10


Formula used:

E = (k*Q)/r^2
 
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Hello, Burger. Welcome to PF!

Did you forget to include the sign of Q1 when you stated Q1 = 14 C?

It is important to always include units with your answers.

Just to be sure that you have a full understanding, what is the interpretation of the negative sign for your answer for the electric field of Q1 at P?

Finally, electric field is a vector. So, it has a magnitude and a direction. Therefore, your final answer for the field at P should include both a magnitude and a direction. The direction should be clearly stated and not left to the reader to interpret.

Otherwise, your numbers look good! (You're getting a very large answer because a Coulomb is a huge amount of static charge.)
 
Q1's charge = -14 C

Thanks for the help! Will ace the Test hopefully. I must just remember to include the direction the N•C^-1
 
OK. Good luck with the test!
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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