- #1
hongiddong
- 65
- 1
I am confused with the wording for a static friction problem; this particular wording also lead me to a conceptual question on the force of static friction. It all started with a question in my textbook that I figured out how to solve for the right answer. The question states, a box of m is sitting on an incline of 45 degrees and it requires an applied force F up the incline to get the box to begin to move. What is the maximum coefficient of static friction? The answer is (F-mgsin45)/mgcos45 by setting the equation as Applied force = mgsinpheta + Force of static fraction. However, the reasoning for the answer states that,"when the object "just begins to move" upwards the forces in both direction are equal and the force of static friction is at its maximum."
My questions:
1.)What does it mean when it says just begins to move or get the box to begin to move, does it mean just before it moves? I think the wording just begins to move means that it has moved(better word is budged) and it got out of the frictional groove that kept it stuck.
2a.)For example, if the applied force was greater than friction static force, the object would have budged out of that groove with the surface, for that moment, with an acceleration. If the force was equal to the friction static force, it would have gotten out of that groove with zero acceleration, but this is where I am confused: I keep thinking there would be a constant velocity that is not zero that budged the object, at the moment, out of the groove of the surface.
2b.)I know that the object should not be moving because an object at rest will have 0 velocity, but what about that initial budge?
Please, I need help understanding this concept?
Thanks Physicsforums!
Jonathan
My questions:
1.)What does it mean when it says just begins to move or get the box to begin to move, does it mean just before it moves? I think the wording just begins to move means that it has moved(better word is budged) and it got out of the frictional groove that kept it stuck.
2a.)For example, if the applied force was greater than friction static force, the object would have budged out of that groove with the surface, for that moment, with an acceleration. If the force was equal to the friction static force, it would have gotten out of that groove with zero acceleration, but this is where I am confused: I keep thinking there would be a constant velocity that is not zero that budged the object, at the moment, out of the groove of the surface.
2b.)I know that the object should not be moving because an object at rest will have 0 velocity, but what about that initial budge?
Please, I need help understanding this concept?
Thanks Physicsforums!
Jonathan