Water flows at speed v in a pipe of radius R. At what speed does the water flow through a constriction in which the radius of th
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Answer:
58.27 N
Explanation:
the data we have is:
mass:
coefficient of friction:
and we also know the acceleration of gravity is
We need to do an analysis of horizontal and vertical forces acting on the object:
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Vertically the forces acting on the object:
- Normal force
(acting up from the object)
- weight:
(acting down from)
so the sum of forces in the vertical axis "y" are:
from Newton's second Law we know that , so:
and since the object is not accelerating in the vertical direction (the movement is only horizontal) , and:
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now let's analyze the horizontal forces
- frictional force:
and since
-->
- force to move the object:
and the two forces just mentioned must be opposite, thus the sum of forces in the "x" axis is:
and we are told that the crate moves at a steady speed, thus there is no acceleration:
and we get:
substituting known values: