Question

The gases and liquids are called fluid. The force exerted by fluid is called drag. It is obvious that when objects move through fluids, they have to overcome friction acting on them. In this process, they lose energy. Efforts are, therefore, made to reduce friction. Birds and fishes have to move about in fluids all the time. Their bodies must have evolved to shapes, which would make them lose less energy in overcoming friction. Such shapes are called streamlined. This is why shapes of aero planes, ships and all vehicles are designed to have shapes, which minimize fluid friction.

i. Friction due to fluids is called
(a) force
(b) pressure
(c) friction
(d) drag
iii. Friction due to air and water can be reduced by suitable designing of the shape of the object. This is called as?
(a) ball bearing
(b) streamlining
(c) lubricants
(d) friction
iii. Which of the following does not have a streamlined shape?
(a) aeroplane
(b) bird
(c) boat
(d) bus
iv. Why do birds and fishes have streamlined bodies?
a) To increase friction
b) To minimize friction
c) All of the above
d) None of these
v. The amount of Frictional force by a fluid on an object depends on
a) The speed of the object with respect to the fluid.
b) The nature of the fluid
c) The shape of the object.
d) All of the above

Answer 1

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Answer 2

Answer:

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Explanation:

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