Rr10302 Applied Mechanics

8/14/2019 Rr10302 Applied Mechanics

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SET-1RRCode.No: 21002

JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD

I .B.TECH SUPPLEMENTARY EXAMINATIONS JANUARY- 2010

APPLIED MECHANICS

(CIVIL ENGINEERING)

Time: 3hours Max.Marks:80

Answer any FIVE questionsAll questions carry equal marks

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1.a) A ball of weight Q = 12 N rests in a right-angled trough, as shown in figure.

Determine the forces exerted on the sides of the trough at D and E if all surfaces are

perfectly smooth.

b) A 675 N man stands on the middle rung of a 225 N ladder, as shown in Figure.

Assuming a smooth wall at B and a stop at A to prevent slipping, find the reactions at

A and B.

[8+8]

2.a) Explain the types of friction with examples.

b) Two equal bodies A and B of weight `W' each are placed on a rough inclined plane.

The bodies are connected by a light string. If A = 1/2 and B = 1/3, show that the

bodies will be both on the point of motion when the plane is inclined at tan-1

(5/12).

[6+10]

3.a) Derive an expression for ratio of tensions of a belt in standard form.

b) The centre of two pulleys of diameter 120 mm and 240 mm are 300 mm apart. They

are connected by an open belt. If the coefficient of friction for the larger pulley be

0.28, w hat would be its value for the smaller pulleys simultaneously? [6+10]


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4.a) Explain the terms:

i) Moment of inertia

ii) Polar moment of inertia

iii) Product of inertia.b) Locate the centroid of the shaded area as shown in the figure. [6+10]

5. Derive the expression for the moment of inertia of a cylinder length l, radius r and

density w about longitudinal centroidal axis and about the centroidal transverse

axis. [16]

6.a) A baloon is ascending with a velocity of 20 m/s above a lake. A stone is dropped to

fall from the balloon and the sound of the splash is heard 6 seconds later. Find the

height of the balloon when the stone was dropped. Velocity of sound is 340 m/s.

b) The acceleration of a particle in rectilinear motion is defined by the relation

a = 25- 4s2

where a is expressed in m/sec2

and s is position coordinate in meters.

The particle starts with no initial velocity at the position s = 0. Determinei) The velocity when s = 3metres

ii) The position where the velocity is again zero

iii) The position where the velocity is maximum. [8+8]

7.a) A body weighing 20 N is projected up a 200

inclined plane with a velocity of 12 m/s,

coefficient of friction is 0.15. Find

i) The maximum distance S, that the body will move up the inclined plane

ii) Velocity of the body when it returns to its original position.

b) Find the acceleration of the moving loads as shown in figure. Take mass of P=120 kg

and that of Q=80 Kg and coefficient of friction between surfaces of contact is 0.3.

Also find the tension in the connecting string. [8+8]


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8.a) A simple pendulum consisting of a bob attached to the cord oscillates in a vertical

plane with a period of 1.5s. The maximum velocity of the bob is 0.5 m/sec. Assuming,

SHM determine:

i) Amplitude of the motion

ii) The max tangential acceleration of the bob.

b) The bob of a simple pendulum of length L = 1.4m is moving with a velocity of 200

mm/s to the right at time t = 0 when = 0. Assuming SHM, determine at t = 1.6s:

i) The angle ii) The magnitudes of the velocity and acceleration of the bob. [8+8]

*****


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APPLIED MECHANICS

(CIVIL ENGINEERING)



- - -







ii) Polar moment of inertiaiii) Product of inertia.

b) Locate the centroid of the shaded area as shown in the figure. [6+10]



axis. [16]


fall from the balloon and the sound of the splash is heard 6 seconds later. Find theheight of the balloon when the stone was dropped. Velocity of sound is 340 m/s.


a = 25- 4s2



The particle starts with no initial velocity at the position s = 0. Determine

i) The velocity when s = 3metres




5/12











SHM determine:





i) The angle

ii) The magnitudes of the velocity and acceleration of the bob. [8+8]



perfectly smooth.


6/12



A and B.

[8+8]




bodies will be both on the point of motion when the plane is inclined at tan-1 (5/12).

[6+10]

*****


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APPLIED MECHANICS

(CIVIL ENGINEERING)



- - -



axis. [16]




b) The acceleration of a particle in rectilinear motion is defined by the relationa = 25- 4s

2where a is expressed in m/sec

2and s is position coordinate in meters.

The particle starts with no initial velocity at the position s = 0. Determine

i) The velocity when s = 3metres













SHM determine:





i) The angle



8/12



perfectly smooth.



A and B.

[8+8]




bodies will be both on the point of motion when the plane is inclined at tan-1

(5/12).

[6+10]






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iii) Product of inertia.


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APPLIED MECHANICS

(CIVIL ENGINEERING)



- - -











SHM determine:





i) The angle



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iii) Product of inertia.




axis. [16]





a = 25- 4s2



The particle starts with no initial velocity at the position s = 0. Determinei) The velocity when s = 3metres



*****

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Rr10302 Applied Mechanics