The answer is A. Hope this helps!!!
No force contributes to density, the density is a physical quantity that is defined as being
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the raport between the mass of the object and its volume. However if you want to measure the density of an object you might want to determine its gravity force (weight)
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from which knowing the gravitational acceleratin you can find its mass
where
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is given in Newtons and
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is given in
Answer:
The behavior of droplets trapped in geometric structures is essential to droplet manipulation applications such as for droplet transport. Here we show that directional droplet movement can be realized by a V-shaped groove with the movement direction controlled by adjusting the surface wettability of the groove inner wall and the cross sectional angle of the groove. Experiments and analyses show that a droplet in a superhydrophobic groove translates from the immersed state to the suspended state as the cross sectional angle of the groove decreases and the suspended droplet departs from the groove bottom as the droplet volume increases. We also demonstrate that this simple grooved structure can be used to separate a water-oil mixture and generate droplets with the desired sizes. The structural effect actuated droplet movements provide a controllable droplet transport method which can be used in a wide range of droplet manipulation applications.
Explanation:
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Kinetic energy is the energy the makes an object move.
If there is no friction, the force that moves the box forward horizontally must be matched by the same force.
If there is friction, then the force moving it forward = frictional force + the additional force you need to add.