- #1
Blangett
- 5
- 0
Homework Statement
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.
Homework 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 separate 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.
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