(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Question Details:

A rope attached to a 19.0 kg wood sled pulls the sled up a 18.0 kg snow-covered hill. A 9.0 kg wood box rides on top of the sled.

If the tension in the rope steadily increases, at what value of the tension does the box slip?

So far none of the answers I have tried has worked. I looked up the friction coefficients. μ=.50 (wood on wood)

μ=.12 (wood on snow)

I have a midterm I am studying for on Friday. I am trying to grasp these types of problems unsuccessfully. Any help you can provide is deeply appreciated.

2. Relevant equations

Where do I go from here? I am stuck on how to proceed. The fact that I am using the net forces of two seperate objects is confusing me. I am not sure what to do with them (do I add the Fnet x together?. Also the fact that I do not have acceleration given is bothering me.

3. The attempt at a solution

Known

fk=μkn

ms=19.0kg

mb=9.0kg

μk=.06 (wood on snow)

μs=.50 (wood on wood)

n=m*g

gx=9.8sinθ m/s2

gy=9.8cosθ m/s2

(Fnetx)sled=T-fk-g

= T-μkn-msg*sinθ=msax

= T-μkmsg *cosθ-msg*sinθ=msax

(Fnety)sled = n-g=msax

= n-msg*cosθ=m*0

n =ms*g*cosθ

(Fnetx)box = -fs-g = mbax

=μs*mb*g*cosθ*mb*g*sinθ =mbax

(Fnety)box= n - g

= n - mb*g*cosθ=mbay

= n - mb*g*cosθ=0

n= mb*g*cosθ

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# Homework Help: Friction, a sled, snow covered hill, sliding box

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