Answer: A
Explanation: the principle of friction with swinging and colliding balls.
Answer:
i) 21 cm
ii) At infinity behind the lens.
iii) A virtual, upright, enlarged image behind the object
Explanation:
First identify,
object distance (u) = 42 cm (distance between object and lens, 50 cm - 8 cm)
image distance (v) = 42 cm (distance between image and lens, 92 cm - 50 cm)
The lens formula,
Then applying the new Cartesian sign convention to it,
Where f is (-), u is (+) and v is (-) in all 3 cases. (If not values with signs have to considered, this method that need will not arise)
Substituting values you get,
i) 
f = 21 cm
ii) u =21 cm, f = 21 cm v = ?
Substituting in same equation
v ⇒ ∞ and image will form behind the lens
iii) Now the object will be within the focal length of the lens. So like in the attachment, a virtual, upright, enlarged image behind the object.
Answer:
It is a liquid because it flows.
Explanation:
because liquids dont have to be a certain color they are liquid as long as they flow
Fluid Dynamics is an area of research that started a long time ago, along with Calculus. It combines techniques of Mathematical Analysis and of Dynamical Systems, such as Bifurcation Theory, among others.
<h3>What is surface tension?</h3>
Surface Tension is a phenomenon that occurs in all liquids, it is characterized by the formation of a kind of elastic membrane at its ends.
<h3>How to calculate the contact angle?</h3>
Contact angles in powders can be measured using the sessile drop measurement in the compressed powder or using the force tensiometer with the Washburn method.
In fluid dynamics, the variables of surface tension, viscosity and contact angle are treated. When dealing with viscosity we have fluid can be viscous or a real fluid. In general, fluids are viscous.
See more about fluid dynamics at brainly.com/question/5144636
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