Drag is defined as the force exerted by the

Drag is the force component exerted on an immersed object,

A

Passing the centroid of the body at 60°to the direction of motion

B

The component being parallel to theflow direction

C

The component being normal to the flow direction

D

None of these

In which of the following the friction drag is generally larger than pressure drag?

A

a circular disc or plate held normal to flow

B

a sphere

C

a cylinder

D

an airfoil

The ratio of wall drag to total drag in the Stoke's law range is

A

0.5

B

1

C

$$\frac{1}{3}$$

D

$$\frac{2}{3}$$

The ratio of the wall drag to the form drag in the Stoke's law range (for motion of spherical particles in a stationary fluid) is

A

0.5

B

1

C

2

D

0.33

In which of the following body shapes, the pressure drag is large compared to the friction drag?

A

Stream line body

B

Two dimensional body

C

Bluff body

D

None of these

গ্রেডিয়েন্ট মধ্যবিন্দুর অবস্থান নির্ধারণ করা যায়-i. নির্ধারণীসূচক সংখ্যা লিখেii. আইকনটি ডানে বায়ে drag করে iii. মুক্ত টুলের সাহায্যে drag করেনিচের কোনটি সঠিক?

A

i ও ii

B

i ও iii

C

ii ও iii

D

i, ii ও iii

The existence of civilized communities, however, is impossible without some element of force, since ambitions who, if unchecked, would soon cause a reversion to anarchy and barbarism. Where force is unavoidable, it should be exerted by the constituted authority in accordance with the will of the community as expressed in the criminal law. The author of passage probably assumes that-

A

prevalence of anarchy is the distinctive feature of a society

B

criminal law expresses the collective will of the community and preserves peace in socity

C

existence of civilization is synonymous with use of force

D

law prevents crime and criminal activities

The force exerted by a jet of water impinging normally on a plate which due to the impact of jet, moves in the direction of jet with a velocity v is

A

$$\frac{{{\text{wa}}\left( {{\text{V}} - {\text{v}}} \right)}}{{2{\text{g}}}}$$

B

$$\frac{{{\text{wa}}\left( {{\text{V}} - {\text{v}}} \right)}}{{\text{g}}}$$

C

$$\frac{{{\text{wa}}{{\left( {{\text{V}} - {\text{v}}} \right)}^2}}}{{2{\text{g}}}}$$

D

$$\frac{{{\text{wa}}{{\left( {{\text{V}} - {\text{v}}} \right)}^2}}}{{\text{g}}}$$

Drag force acting on a body does not depend upon the

A

Density of the fluid

B

Density of the body

C

Velocity of the body

D

Projected area of the body

In the low Reynolds number region, the drag force on a sphere is proportional to

A

V

B

V²

C

V⁴

D

V^0.5

Drag is defined as the force exerted by the

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