How Far Will a Bundle Slide Up an Incline with Friction?

[h7u9i]

A 4.0 kg bundle starts up a 30° incline with 128 J of kinetic energy. How far will it slide up the plane if the coefficient of friction is 0.30?So, I began finding the Normal
N=W(y)=4cos30=3.46

Then found friction

f=uN
f=.3*3.46=1.04

So
E=E
K=Ug + Q
K=mgh + fd
K=mg(dsin30)+fd
128=4(9.8)(.5)d+(1.04)d
128=20.64d
d=6.2m

But the answer says 4.3m. What's wrong?

Thanks!

EDIT:
So I figured it out... N=4*9.8cos30. Duh.

 

[Redbelly98]

So I figured it out...

Glad things worked out. By the way, welcome to Physics Forums!

 

[Ghostscythe]

I had a similar problem (just the numbers changed). I get the whole h = dsin(30) thing, but why does Fn = mgcos(30)?

 

[Redbelly98]

I had a similar problem (just the numbers changed). I get the whole h = dsin(30) thing, but why does Fn = mgcos(30)?

Draw a free body diagram. Take the direction of the normal force as the y-direction, apply F_net=ma to the y-direction, and solve for F_n.