St.MARTIN’S ENGINEERING COLLEGEDHULAPALLY, SECUNDERABAD-14

I B TECH – 2016-17I MID EXAMINATION QUESTION PAPER

Course Name ENGINEERING MECHANICSCourse Code ME105ES

Branch ME ,CE,ECE,EEE,IT,CSE

UNIT –I

PART -AS.NO Question Blooms Taxonomy

LevelCourse

outcome1

What is engineering mechanics?Knowledge

1

2Explain the types of system of forces? Knowledge

1

3Define a couple? Knowledge

1

4Explain briefly about system of forces? Comprehension 2

5Define moment? Comprehension 2

6What is the resultant of force system? Knowledge 1

7 Define free body diagram? Knowledge 3

8Explain the classification of engineering mechanics?

Comprehension 2

9Define the term statics and kinetics

Comprehension 2

10

Define forceand state its specifications?

Comprehension 1

11 Explain briefly about types of coplanar forces? Comprehension

2

12 Explain briefly about types of non coplanar forces? Knowledge

1

13 What is equilibriant Knowledge 1

14 State parallelogram law of forces Comprehension 2

15 Define the term moment of force Knowledge 1

PART -B1

A system of loads acting on a beam as shown in the fig. Determine the resultant of the loads.

Comprehension

2

2 Two spheres, of each of weight 1000 N and radius of 25 cm rest in horizontal channel of width 90 cm as shown in fig 1. Find the reactions on the points of contact A, B and D

Knowledge

1

3 Find resultant of given system of forces as shown in fig

Knowledge

1

4 Forces P1,P2,and P3 of magnitudes 20KN,30Knand 45KN are concurrent in space at the origin O(0,0,0) and are directed through the points A(3,2,4),B(2,6,5) and C(3,-3,5)respectively. Determine the resultant of the system of forces

Knowledge

1

5 A ball of weight Q = 12 N rests in a right - angled trough, as shown in fig 1. Determine the forces exerted on the sides ofthe

Evaluation 2

trough at D (RD) and E (RE) if all surfaces are perfectly smooth.

6 Find the resultant of the force system?

Knowledge

1

7 Two smooth spheres each of radius 100mm and weight 100N rest on a horizontal channel having vertical walls and the distance b/w which is 360mm. Find the reactions at the points of contacts A, B, C and D.?

Knowledge

1

8 Forces P1 ,P2 , P3,∧P4 of magnitude 10kN, 20kN, 25kN and 40kN are concurrent in space and are directed through the points A(3, 2, 5) , B(1,7,4) C(4, -2, 4) and D(-2, 4, -3) respectively. Determine the resultant of the system of forces. Given the system forces are concurrent at the origin

Knowledge

1

9 A system of loads acting on a beam is shown. Determine the resultant of the loads.

Knowledge 1

10 Two identical rollers, each of weight 100 N, are supported by an inclined plane and a vertical wall as shown in figure below. Assuming smooth surfaces, find the reactions induced at the points of support A, B and C

.

Knowledge1

PART -C1 A system of connected flexible cables shown in figure is

supporting two vertical forces 200 N and 250 N at points B and D. Determine the forces in various segments of the able.

Analysis 3

2 Two identical rollers each of weight 50N are supported by an inclined plane and a vertical wall as shown in fig. Find the reactions at the points of supports A, B, and C.

Analysis 3

3 Two smooth circular cylinders each of weight 1000 N and radius 15 cm are connected at their centers by a string AB of length 40 cm and rest upon a horizontal plane, supporting above them a third cylinder of weight 2000 N and radius 15 cm as shown in Figure. Predict the force S in the string AB and reactions on the floor at the points of contact D and E.

Analysis 3

4 Determine the resultant of system of forces acting as shown in fig.

Analysis 3

5 The forces shown in the figure below are in equilibrium. Determine the forces F1 and F2

Analysis 3

6 A cylindrical roller has a weight of 10kN and it is being pulled by a force which is inclined at 30° with

the horizontal as shown in fig. While moving it comes across an obstacle of 10cm height. Predict the force required to cross this obstacle when the diameter of

Analysis 3

the roller is 70cm.

7Find the resultant of system of forces

Analysis 3

8 Find the resultant of system of forces Analysis 3

9 Find the resultant of system of forces Analysis 3

10 Find the resultant of system of forces Analysis 3

UNIT –II

PART -AS.NO Question Blooms

TaxonomyLevel

Course outcome

1Define friction? Knowledge

1

2Define the coefficient of friction? Analysis

33 Define the angle of friction? Comprehension 2

4 Explain laws of friction? Knowledge 1

5 Explain briefly about static friction? Knowledge 1

6 What is the principle of a screw jack? Knowledge 17

Define the efficiency of screw jack. Knowledge 1

8 Explain briefly about Dynamic friction?Analysis

3

9 What is the principle of a Differential screw jack?

Comprehension 2

10What is a wedge? Knowledge

1

11What is differential screw jack

Knowledge 1

12What is angle of repose?

Analysis 3

13Explain different types of friction

Comprehension 2

14What is dynamic friction

Knowledge 1

15What is ladder friction

Knowledge 1

PART -B1 What is the value of P in the system? The motion of

500N block to the right side and coefficient of friction between is 0.20?

Analysis

3

2 A block over lying a 10 ͦwedge on a horizontal floor and leaning against a vertical wall and weighing 1500N is to be raised by applying horizontal force to the wedge. Assume the coefficient of friction between all the surfaces in contact to be 0.3. Determine the minimum horizontal force to be applied to raise the block

Evaluation 4

4 a)Explain the workingprincipleofscrew jack with neat sketch?

Knowledge 1

5 Explain the working principle of differential screw jack with neat sketch?

Evaluation 4

6 Block A weighing 1000 N rest over block B which weighs 200N as shown in figure below. Block A is tied to wall with a horizontal string. The coefficient of friction between block A and B is 0.25 and between B and floor is 1/3, what should be the value of P to move the block B, if

(i) P is horizontal(ii) P acts at 30 ° upwards to

horizontal.

Knowledge 1

7 The following particulars refer to a screw jack:

Diameter of screw rod = 62.5 mm.

Length of the handle = 250 mm.

Pitch of the square thread = 12.5 mm.

Coefficient of friction = 0.05.

(i) Find the effort required to lift up a load of

5000 N.

(ii) Find the effort required to lift down a load

Analysis 3

of 5000 N.

8 Outside diameter of a square threaded spindle of a

screw Jack is 40mm. The screw pitch is 10mm. If the

coefficient of friction between the screw and the nut

is 0.15, neglecting friction between the nut and

collar, length of the lever 500mm determine

i. Force required to be applied at the screw to

raise a load of 2000N

ii. The efficiency of screw jack

iii. Force required to be applied at pitch radius

to lower the same load of 2000N and

iv. Efficiency while lowering the load

Knowledge 1

9 The following are the specifications for a differential

screw jack:

i) Pitch of the smaller screw is 5mm

ii) Pitch of the larger screw is 10mm

iii) Lever arm length from center of screw is 500mm

The screw jack raises a load of 15KN with an effort of

185N. Determine the efficiency of the differential screw

jack at this load.

Evaluation 4

10 A 400 N block is resting on a rough horizontal

surface for which the coefficient of friction is 0.40.

Determine the force P required to cause motion to

impend if applied to the block (a) horizontally or (b)

downward at 30° with the horizontal.

Knowledge 1

PART -C1 Two blocks are connected by a weight less solid rod attached

to each block with frictionless pins. If the coefficient of

friction under each block is 0.25 and B weighs 2700 N, find

Knowledge 1

the minimum weight of A to prevent motion.

2 Two blocks A and B are connected by a horizontal string . The coefficient of friction under the upper block A is 0.3 and the lower block B is 0.6. Weights of the block A and B are 120N and 95N. Find out tension in the string and reaction at contact point?

Evaluation 4

3 Two blocks A and B of weights 500 N and 750 N respectively are connected by a cord that passes over a frictionless pulley, as shown in figure. The coefficient of friction between the block A and the inclined plane is 0.4 and between the block B and the inclined plane is 0.3. Determine the force P to be applied to block B to produce the impending motion of block B down the plane.

Knowledge 1

4 A block (A) weighing 1 kN rests on a rough inclined plane whose inclination to the horizontal is 45°. This block is connected to another block (B) weighing 3 kN rests on a rough horizontal plane by a weightless rigid bar inclined at an angle

Analysis 3

of 30° to the horizontal as shownFind horizontal force (P) required to be applied to the block (B) just to move the block (A) in upward direction. Assume angle of limiting friction as 15° at all surface where there is sliding.

5 Two blocks A and B of weight 100 N and 300 N respectively are resting on a rough inclined plane as shown Find the value of the angle (θ) when the block B is about to slide. Take coefficient of friction between the two blocks as well as block B and the inclined plane as 0.25

Analysis 3

6 A block (A) weighing 1 kN rests on a rough inclined plane whose inclination to the horizontal is 45°. This block is connected to another block (B) weighing 3 kN rests on a rough horizontal plane by a weightless rigid bar inclined at an angle of 30° to the horizontal as shown

Find horizontal force (P) required to be applied to the block (B) just to move the block (A) in upward direction. Assume angle of limiting friction as 15° at all surface where there is sliding.

Analysis 3

7 The blocks shown in Fig. are connected by flexible, inextensible cords passing over frictionless pulleys. At A the coefficients of friction are μs = 0.30 and μk = 0.20 while at B they are μs = 0.40 and μk = 0.30. Compute the magnitude and direction of the friction force acting on each block

Analysis 3

8 A uniform ladder 4.8 m ft long and weighing W lb is placed

with one end on the ground and the other against a vertical

wall. The angle of friction at all contact surfaces is 20°. Find

the minimum value of the angle θ at which the ladder can be

inclined with the horizontal before slipping occurs

Analysis 3

9 Two blocks each weighing 1.5 kNare connected by a uniform

horizontal bar which weighs 1.0 kN. If the angle of friction is

15° under each block, find P directed parallel to the 45° incline

that will cause impending motion to the left

Analysis 3

10 What force P must be applied to the wedges shown in Fig. to

start them under the block? The angle of friction for all contact

surfaces is 10°

Analysis 3

UNIT –III

PART -A1 Explain difference between centroid and

center of gravity?Comprehension 2

2Define a centroid?

Knowledge 1

3State and prove theorem of Pappus?

Evaluation 2

4Define a centre of gravity?

Knowledge 1

5 Explain the types of theorem of Pappus?

Knowledge 1

6 Find the centroid of the plane lamina shown in fig

Knowledge 1

7 Find the centroid of the plane lamina shown in fig

Knowledge1

8 What is centroidal axis Comprehension 2

9 What are coordinates of centroid of triangle Knowledge 1

10 What is the position of centroid of semi circle

Evaluation

11 What are coordinates of centroid of quadrant Knowledge 1

12 What is the moment of area about coordinate Knowledge 1

axes?13 What is position of centre of gravity of solid

coneComprehension 2

14 What are the theorems to be used to find surface area and volumes?

Knowledge 1

15 What is the centroid of semi circular arc? Knowledge 1

PART -B1 a) Find the centroid of the plane lamina shown in fig Knowledge

1

2 Find the centroid of the plane lamina shown in fig Knowledge 1

3 . Find the centroid of the shaded area. Knowledge 1

4. Find the centroid of the shaded area.

Knowledge 1

5

Find the centroid of the plane lamina shown in fig

Knowledge 1

6 State and prove Pappus-Guldinus First theorem Knowledge 1

7 State and prove Pappus-Guldinus Second theorem Knowledge 1

8 Derive an expression for the centroid and centre of gravity

Knowledge 1

PART -C1 Find the centroid of the shaded area. Analysis 3

2 Find the centroid of the shaded area. Radius of semi circle is 50

Analysis 3

3 Find the centroid of the shaded area.All the dimensions are in cm

Analysis 3

4

Find the centroid of the shaded area.All the dimensions are in cm

5 . Find the centroid of the shaded area. Analysis 3

6 . Find the centroid of the shaded area. Analysis 3

7

Find the centroid of plane lamina?

Analysis 3

8 Find the centroid of the shaded area. Analysis 3

Course faculty

T. Paramesh

G.V. Rao

B . Bheema raj

R. Rajasanthosh kumar

Ch. Srinivas