Find magnitude of acceleration on a Ca ion, given electric field.

AI Thread Summary
The discussion focuses on calculating the acceleration of a Ca+1 ion in an electric field of 10^7 N/C. The user initially calculated the force using the charge of the ion and the electric field, leading to confusion about the correct mass to use for the ion. After confirming the use of the charge of +1.6 x 10^-19 C and the atomic mass unit of 1.66 x 10^-27 kg, the user recalculated the force and acceleration. Ultimately, they found the correct acceleration value of 2.41 x 10^13 m/s² after clarifying the atomic mass of calcium. The thread highlights the importance of using accurate values for charge and mass in physics calculations.
monnapomona
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Homework Statement



The electric field strength across a typical cell membrane is about 107 N/C. Given this information, find the magnitude of the acceleration of a single charged Ca+1 ion as it penetrated throught the cell wall. Ignore any resistive forces.
One atomic mass unit is 1.66 x 10-27 kg.

Homework Equations


F = ma
F=q0E

The Attempt at a Solution



I was thinking of multiplying the charge with how many protons a Ca ion has so:

F=q0E
= (20\bullet1.6*10-19C)(107 N/C)
= 3.2*10-11 N

Then I manipulated for acceleration in F=ma and got 1.93*1016 m/s?

Is this the correct method for finding the magnitude of acceleration?
 
Physics news on Phys.org
Ca1+ means that the charge on the ion is only unbalanced by ONE proton charge. I.e. the atom has lost one electron, leaving it with a net positive charge due to ONE extra proton whose charge is unbalanced.
 
cepheid said:
Ca1+ means that the charge on the ion is only unbalanced by ONE proton charge. I.e. the atom has lost one electron, leaving it with a net positive charge due to ONE extra proton whose charge is unbalanced.

So would it be correct if I just use q=+1.6*10-19 C in the formula to find force?
 
Last edited:
monnapomona said:
So would it be correct if I just use q=+1.6*10-19 C in the formula to find force?

Yes.
 
cepheid said:
Yes.

Okay so I used q=+1.6*10-19 C in the formula and got F = 1.6*10-12 N. To find the magnitude of acceleration, I manipulated for a in F = ma and got 9.64 * 1014 m/s as the answer but I inputted it in my online homework assignment and apparently it's wrong.

Should I use a different formula to find acceleration?

Edit: I used 1.66*10-27 kg as the mass.
 
monnapomona said:
I used 1.66*10-27 kg as the mass.
That's one atomic mass unit. How many of those per calcium atom?
 
haruspex said:
That's one atomic mass unit. How many of those per calcium atom?

To get atomic mass, do I need to add protons and neutrons in Calcium together? So 40?
 
monnapomona said:
To get atomic mass, do I need to add protons and neutrons in Calcium together? So 40?

Sounds about right to me.
 
cepheid said:
Sounds about right to me.

Sweet, I got the answer right! (2.41*1013 m/s) Thanks for all your help everyone! :D
 

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