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DR. BABASAHEB AMBEDKAR TECHNOLOGICAL UNIVERSITY, LONERE

Semester Examination – May/June 2019

First Year (I/II Semester) B. Tech. (All)

Sub: ENGINEERING MECHANICS (ME102/ME202)

Time: 03 Hours

Date: 01/06/2019

Max Marks: 60

INSTRUCTIONS TO THE STUDENTS

1

. Attempt any five questions. Each question carries 12 marks.

2

3

. Illustrate your answers with neat sketches, diagrams etc. where ever necessary.

. Necessary data is given in the respective questions. If such data is not given, it means that

the knowledge of that data is a part of the examination.

4

. If some part or parameter is noticed to be missing, you many appropriately assume it and

should mention it clearly.

_

____________

_____________________________________

____ __(Marks)

Q.1. (a) Define: Resultant force, Coplanar forces, and Moment of a force.

(6)

(

b) Find the magnitude and direction of the resultant force for a number of (6)

forces acting at a common point:

i) 600 N inclined at 45° towards South of West.

ii) 800 N towards South-East,

iii) 400 N inclined at 30° towards North of East

iv) 300 N towards North-West

iv) 500 N towards North

Q.2. (a) List for the following: Types of beams, and types of supports.

(4)

(8)

(b) Find the support reactions for a simply supported beam shown in fig. 1.

1

50 kN

1

00 kN

2

00 kN/m

2

m

3 m

1

0 m

OR

(

b) Find magnitude and nature of forces in members of a truss shown in Fig.

00

(8)

1

4

5°

1

m

1 m

1 m

1

m

1

1

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Q.3. (a) Define friction and state laws of static friction and dynamic friction.

(6)

(

b) A uniform ladder of 4 m length rests against a vertical wall with which it (6)

makes an angle of 45°. The coefficient of friction between the ladder and

the wall is 0.4 and that between ladder and the floor is 0.5. If a man,

whose weight is one-half of that of the ladder, ascends it, how high will it

be when the ladder slips?

Q.4. (a) Motion of a particle along a straight line is given by the equation:

(4)

x = t^{3} - 3t^{2} - 9 t + 12

Determine the time, position and acceleration of the particle when its

velocity becomes zero.

(

b) The distance between two stations A and B is 3.9 km. A train starts from (8)

station A and reach its speed 30 kmph in 20 seconds and travels until the

speed reaches 36 kmph. This speed is maintained until brakes are

applied and the train is brought to rest at the second station B under the

retardation of 0.9 m/s^{2}. Find the time taken to perform this journey.

Q.5. Solve any two:

(

(

a) State and explain in brief D’Alembert’s principle.

(6)

b) A motorist is traveling on a curved road of radius 200 m at a speed of 72 (6)

kmph. Find the normal and tangential components of acceleration.

(

c) Boat A is moving north-west at a speed of 36 km/h and the boat B is (6)

moving east at speed 18 km/h. Find the magnitude and direction of the

relative velocity of the boat B with respect to the boat A.

Q.6. Solve any two:

(

(

a) State: The work-energy principle for a system of particles.

(6)

b) A man of mass 60 kg dives vertically downwards into a swimming pool (6)

from a tower of height 20 m. He was found to go down in water by 2 m

and then started rising. Neglect the air resistance. Find the average

resistance of the water.

(

c) An army truck of mass 5 tonnes (t) has tractive resistance of 150 N/t. (6)

Find the power required to propel the truck at a uniform speed of 36

km.p.h. (a) up an incline of 1 in 100 ; (b) on a level track ; and (c) down an

incline of 1 in 100.

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