A Playground Slide and Some Friction

[ccgrad05x2]

A child goes down a playground slide that is inclined at an angle of 28.0° below the horizontal. Find the acceleration of the child given that the coefficient of kinetic friction between the child and the slide is 0.415

Heres what I have so Far:
F - fk = ma
mgsin0 - MkN = ma
mgsin0 - Mkmgcos0 = ma
gsin0 - mkcos0 = a

so by this,

a = 9.8sin28 - .415cos28
= 4.2343

I cannot figure out what I am doing wrong here


thanks friends

 

[hage567]

a = 9.8sin28 - .415cos28

There should be a g in there. You dropped it somewhere along the way.

 

[ccgrad05x2]

So, just because it is my last submission on this problem the answer should then be:

a = (9.8sin28) - (9.8 x .415 cos28)

such a stupid mistake...thanks

 

[hage567]

Seems reasonable to me.