Friction/Inclined plane question, help would be appreciated

[jami8337]

Friction/Inclined plane question, help would be appreciated :)

A box is sent sliding up a plane, inclined to the horizontal at 25.0◦ with an
initial speed of 3.0 m/s.
The coefficient of kinetic friction between the box
and the plane is 0.17. How far up the plane does the box go before coming to
rest



f=F\mu



I rearange the equations using F=ma, using trig etc, and i don't get the answer which is supposedly 0.8m

Thanks

 

[cupid.callin]

I rearange the equations using F=ma, using trig etc, and i don't get the answer which is supposedly 0.8m

Please explain how you got a result, and what the result was ...

 

[jami8337]

I got, F=mgcos25
and fk(kinetic friction) = 0.17mgcos25

then
f=ma
hence
fk+mgsin25=f
ma=0.17mgcos25+mgsin25
a=0.17gcos25+gsin25
=5.66m/s^2

i then put that into v^2=u^2+2ax

and got x=0.14

 

[cupid.callin]

You did something wrong here

i then put that into v^2=u^2+2ax

and got x=0.14

Try it again ...

 

[jami8337]

ah thank you, was for some reason doing a^2 :)

 

[cupid.callin]

ah thank you, was for some reason doing a^2 :)

You're Welcome !