The block moves with constant velocity: for Newton's second law, this means that the resultant of the forces acting on the block is zero, because the acceleration is zero.
We are only concerned about the horizontal direction, and there are only two forces acting along this direction: the force F pushing the block and the frictional force

acting against the motion. Since their resultant must be zero, we have:

The frictional force is

where

is the coefficient of kinetic friction

is the weight of the block.
Substituting these values, we find the magnitude of the force F:
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a. I've attached a plot of the surface. Each face is parameterized by
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with
and
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with
and
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with
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with
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with
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b. Assuming you want outward flux, first compute the outward-facing normal vectors for each face.





Then integrate the dot product of <em>f</em> with each normal vector over the corresponding face.










c. You can get the total flux by summing all the fluxes found in part b; you end up with 42π - 56/3.
Alternatively, since <em>S</em> is closed, we can find the total flux by applying the divergence theorem.

where <em>R</em> is the interior of <em>S</em>. We have

The integral is easily computed in cylindrical coordinates:


as expected.
Answer. dry friction- <span> resists relative lateral motion of two solid surfaces in contact.</span>
Answer:
the second one!
Explanation:
the question is well, the question, a hypothesis is an educated guess on what you think will be the outcome