JNTU Kakinada B-Tech 3-2 PT32051/RA I ENGINEERING MECHANICS R13 April 2018 Question Paper

Code No: PT32051/RA
III B. Tech II Semester Supplementary Examinations, April – 2018
ENGINEERING MECHANICS (Civil Engineering)Time: 3 hours Max. Marks: 70
Note: 1. Question Paper consists of two parts (Part-A and Part-B) 2. Answering the question in Part-A is compulsory
3. Answer any THREE Questions from Part-B
*****
PART ?A
1 a) What is limiting friction? [3M]
b) Write equilibrium equations for coplanar systems. [4M]
c) Distinguish between centroid and centre of Gravity. [4M]
d) What is products of Inertia. [4M]
e) A particle, starting from rest, moves in a straight line, whose equation of motion is
given by : S = t
3
? 2t
2
+ 3. Find the velocity and acceleration of the particle after 5
seconds.
[3M]
f)Write the applications of Work ? energy method.
[4M]
PART -B
2 a) Two forces of magnitude 240 N and 200 N are acting at a point O as shown in fig.
below. If the angle between the force is 60
0
, Determine the magnitude of the
resultant force. Also determine the angle ? and ? as shown in fig. below
[8M]
b) A load of 500 N is lying on an inclined plane, whose inclination with the horizontal
is 30?. If the coefficient of friction between the load and the plane is 0.4, find the
minimum and maximum horizontal force, which will keep the load in equilibrium.
[8M]
3 a) State and Prove Lami?s Theorem.
[8M]
b) An electric light fixture weighting 15 N hangs from a point C, by two strings AC
and BC. The string AC is inclined at 60? to the horizontal and BC at 45? to the
horizontal as shown in Fig.Using Lami?s theorem, or otherwise, determine the
forces in the strings AC and BC.
[8M]
R13
SET – 1
1 of 3

Code No: PT32051/RA
III B. Tech II Semester Supplementary Examinations, April – 2018
ENGINEERING MECHANICS (Civil Engineering)Time: 3 hours Max. Marks: 70
Note: 1. Question Paper consists of two parts (Part-A and Part-B) 2. Answering the question in Part-A is compulsory
3. Answer any THREE Questions from Part-B
*****
PART ?A
1 a) What is limiting friction? [3M]
b) Write equilibrium equations for coplanar systems. [4M]
c) Distinguish between centroid and centre of Gravity. [4M]
d) What is products of Inertia. [4M]
e) A particle, starting from rest, moves in a straight line, whose equation of motion is
given by : S = t
3
? 2t
2
+ 3. Find the velocity and acceleration of the particle after 5
seconds.
[3M]
f)Write the applications of Work ? energy method.
[4M]
PART -B
2 a) Two forces of magnitude 240 N and 200 N are acting at a point O as shown in fig.
below. If the angle between the force is 60
0
, Determine the magnitude of the
resultant force. Also determine the angle ? and ? as shown in fig. below
[8M]
b) A load of 500 N is lying on an inclined plane, whose inclination with the horizontal
is 30?. If the coefficient of friction between the load and the plane is 0.4, find the
minimum and maximum horizontal force, which will keep the load in equilibrium.
[8M]
3 a) State and Prove Lami?s Theorem.
[8M]
b) An electric light fixture weighting 15 N hangs from a point C, by two strings AC
and BC. The string AC is inclined at 60? to the horizontal and BC at 45? to the
horizontal as shown in Fig.Using Lami?s theorem, or otherwise, determine the
forces in the strings AC and BC.
[8M]
R13
SET – 1
1 of 3

4 Determine the centroid for the following figure:

[16M]
5 Find the moment of inertia of the section as shown in the fig about centroidal axis
XX perpendicular to the web.

2 of 3
[16M]
R13
SET – 1
Code No: PT32051/RA

Code No: PT32051/RA
III B. Tech II Semester Supplementary Examinations, April – 2018
ENGINEERING MECHANICS (Civil Engineering)Time: 3 hours Max. Marks: 70
Note: 1. Question Paper consists of two parts (Part-A and Part-B) 2. Answering the question in Part-A is compulsory
3. Answer any THREE Questions from Part-B
*****
PART ?A
1 a) What is limiting friction? [3M]
b) Write equilibrium equations for coplanar systems. [4M]
c) Distinguish between centroid and centre of Gravity. [4M]
d) What is products of Inertia. [4M]
e) A particle, starting from rest, moves in a straight line, whose equation of motion is
given by : S = t
3
? 2t
2
+ 3. Find the velocity and acceleration of the particle after 5
seconds.
[3M]
f)Write the applications of Work ? energy method.
[4M]
PART -B
2 a) Two forces of magnitude 240 N and 200 N are acting at a point O as shown in fig.
below. If the angle between the force is 60
0
, Determine the magnitude of the
resultant force. Also determine the angle ? and ? as shown in fig. below
[8M]
b) A load of 500 N is lying on an inclined plane, whose inclination with the horizontal
is 30?. If the coefficient of friction between the load and the plane is 0.4, find the
minimum and maximum horizontal force, which will keep the load in equilibrium.
[8M]
3 a) State and Prove Lami?s Theorem.
[8M]
b) An electric light fixture weighting 15 N hangs from a point C, by two strings AC
and BC. The string AC is inclined at 60? to the horizontal and BC at 45? to the
horizontal as shown in Fig.Using Lami?s theorem, or otherwise, determine the
forces in the strings AC and BC.
[8M]
R13
SET – 1
1 of 3

4 Determine the centroid for the following figure:

[16M]
5 Find the moment of inertia of the section as shown in the fig about centroidal axis
XX perpendicular to the web.

2 of 3
[16M]
R13
SET – 1
Code No: PT32051/RA

6 A projectile fired from the edge of a 150 m high cliff with an initial velocity of 180
m/s at an angle of elevation of 30? with the horizontal. Neglecting air resistance
find (i) The greatest elevation above the ground reached by the projectile (ii) Horizontal distance from the gun to the point, where the projectile strikes the
ground
[16M]
7 A body of weight 1 KN is on the horizontal surface of a table. This weight is
connected to another body of weight 2 KN by a string passing over a smooth pulley
fixed at the corner of the table. The coefficient of friction between 1 KN weight and
the table surface is 0.20. If the system is released from rest, find the velocity of 2
KN weight after it has moved 1.2 m using the work-energy method.
[16M]
*****
3 of 3
R13
SET – 1
Code No: PT32051/RA