# Inclined plane, Calculate friction force

## Homework Statement Wnet = Ek

## The Attempt at a Solution

1) That was fine.
2) I just want to confirm if this answer is right?, I got 12.28N. Used work energy theorem.

Sorry for double post, edited the title

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haruspex
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2020 Award

## Homework Statement Wnet = Ek

## The Attempt at a Solution

1) That was fine.
2) I just want to confirm if this answer is right?, I got 12.28N. Used work energy theorem.

Sorry for double post, edited the title
Seems a bit high. Pls post your working.

Seems a bit high. Pls post your working.
Sorry my mistake, forgot something in my calculation. Anyway heres my working

Wnet = Ek
Wg + Wf + Wn = 1/2*m(vf^2 - vi^2)
(5*9.8*sin30*20) - 20Ff + 0 = 1/2*5(12^2 - 6^2)...That 20 is the length of the incline
Ff = 11N.........Now correct?

haruspex
Homework Helper
Gold Member
2020 Award
Sorry my mistake, forgot something in my calculation. Anyway heres my working

Wnet = Ek
Wg + Wf + Wn = 1/2*m(vf^2 - vi^2)
(5*9.8*sin30*20) - 20Ff + 0 = 1/2*5(12^2 - 6^2)...That 20 is the length of the incline
Ff = 11N.........Now correct?
Yes, that looks right.

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