Homework Help

A chlorine ion (Cl^- ) with a mass of 5.85*10^-26 kg is projected with an energy of...

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breadline | Student, Grade 9 | (Level 1) Honors

Posted April 4, 2012 at 11:12 AM via web

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A chlorine ion (Cl^- ) with a mass of 5.85*10^-26 kg is projected with an energy of 8.50 keV perpendicularly into a magnetic field with a strength of 0.650 T.

 

A. what is the kinetic energy of the chlorine ion, in joules?

B. what is the speed of the chlorine ion?

For A, I got 1.36*10^-15 J

I don’t know how to figure B...Help please? Is a correct?

 

Thanks!

1 Answer | Add Yours

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jerichorayel | College Teacher | (Level 1) Senior Educator

Posted April 10, 2013 at 5:38 AM (Answer #1)

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Your answer for letter A is correct!

For the next question, we can use the formula for the kinetic energy:

`KE = 1/2 mv^2`

To solve for the speed of the chlorine ion, we should arrange the formula a little bit.

`2 KE = mv^2`

`(2 KE)/(m) = v^2`

`sqrt((2 KE)/(m) = v^2)`

`v = sqrt((2 KE)/(m))`

Given:

  • KE = `1.36x10^-15 Jou l es or (kg*m^2)/(s^2)`
  • m = `5.85x10^-26 kg`

`v = sqrt((2 * (1.36*10^-15))/(5.85x10^-26))`

`v = 215, 628.674 m/s or 2.16x10^5 m/s` -> final answer

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