- #1
LCSphysicist
- 645
- 161
- Homework Statement
- nothing
- Relevant Equations
- nothing
Exercise like this:
I think that the friction force can assume two direction, up and down, but how can i know the direction of the force?
I want to say, i don't even know which mass is greater to say i the block will upward or downward.
that is the doubt.
That is the correct forces directions:
[how can i know that is the right direction to friction force?]
The only answer i wonder is, if i choose the wrong direction, eventually i will fall into absurdity, that is, the magnitude force will be negative, but the magnitude is only positive, so that is the absurdity
I think that the friction force can assume two direction, up and down, but how can i know the direction of the force?
I want to say, i don't even know which mass is greater to say i the block will upward or downward.
that is the doubt.
That is the correct forces directions:
[how can i know that is the right direction to friction force?]
The only answer i wonder is, if i choose the wrong direction, eventually i will fall into absurdity, that is, the magnitude force will be negative, but the magnitude is only positive, so that is the absurdity