Thank you for the welcome!
I considered this and thought I had done right when instead of multiplying the mass of the object by just gravity, as is the case when the object is on a flat surface, I multiplied the mass by the y component of its weight. I see now where I went wrong because that...
Homework Statement
A rope attached to a 19.0 kg wood sled pulls the sled up a 19.0° snow-covered hill. A 14.0 kg wood box rides on top of the sled.
EDIT: the actual question to be answered, oops.
What's the magnitude of the tension that will cause the box to slide?
Mass of box (mb) = 14.0kg...