# K=1/2mv^2 simple physics question

## Homework Statement

A ball whose mass is 8kg travels at a velocity [PLAIN]https://s3.lite.msu.edu/adm/jsMath/fonts/cmsy10/alpha/144/char68.png22,79,6[PLAIN]https://s3.lite.msu.edu/adm/jsMath/fonts/cmsy10/alpha/144/char69.pngm[PLAIN]https://s3.lite.msu.edu/adm/jsMath/fonts/cmmi10/alpha/144/char3D.pngs. [Broken] What is the rest energy of the ball?[/B]

K=1/2 mv^2[/B]

## The Attempt at a Solution

K=1/2 (8) v^2

Im not sure what to do with velocity since its in vector form, I tried taking the magnitude of it but that was incorrect.[/B]

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SteamKing
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## Homework Statement

A ball whose mass is 8kg travels at a velocity [PLAIN]https://s3.lite.msu.edu/adm/jsMath/fonts/cmsy10/alpha/144/char68.png22,79,6[PLAIN]https://s3.lite.msu.edu/adm/jsMath/fonts/cmsy10/alpha/144/char69.pngm[PLAIN]https://s3.lite.msu.edu/adm/jsMath/fonts/cmmi10/alpha/144/char3D.pngs. [Broken] What is the rest energy of the ball?[/B]

K=1/2 mv^2[/B]

## The Attempt at a Solution

K=1/2 (8) v^2

Im not sure what to do with velocity since its in vector form, I tried taking the magnitude of it but that was incorrect.[/B]
The problem is asking for the 'rest energy' of the ball. I don't think you need to know the velocity of the ball in order to calculate its rest energy.

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haruspex