Supplementary Examinations, December 2017
(Regulations: VCE-R15)
ENGINEERING MECHANICS-I
(Common to Mechanical Engineering Civil Engineering)
Date: 29 December, 2017
Time: 3 hours
Max Marks: 75
Answer ONE question from each Unit
All Questions Carry Equal Marks
Unit I
1.

Explain the different types of force systems giving an example for each one of them.
7M

Determine the resultant of the five forces shown in Fig.1.
Fig.1
8M
2.

A force F1 1200N is acting vertically on an incline as shown in Fig.2. Find its components along x and y axes.
Fig.2
7M

A 3kN crate is to be supported by the rope and pulley arrangement shown in Fig.3 Determine the magnitude and direction of the force which should be exerted at the free end of the rope.
Fig.3
8M
Cont…2

Unit II
3.

Define free body diagram. Describe types of forces acting on a body. Explain them briefly.
7M

Determine the reactions at contact points for the system shown in Fig.4.
Fig.4
8M
4.

Write a note on:
i. Roller Support
ii. Hinged Support
iii. Fixed Support
7M

Determine the equivalent system of force and couple at for the system of loading as shown in Fig.5.
Fig.5
8M
Unit III
5.
A ladder is supported against a wall as shown in Fig.6. It weighs 250N and a man of weight 500N force to climb the entire ladder, determine how far can be climb along the ladder without slipping. Coefficient of friction between floor and ladder is 0.25 and between wall and ladder is 0.15.
Fig.6
15M
Cont…3
3
6.

Briefly explain:
i. Angle of repose
ii. Cone of friction
5M

Determine whether the 50kg block shown in Fig.7 is in equilibrium and find the magnitude and direction of the frictional force:
i.
ii.
Take μ=0.3.
Fig.7
10M
Unit IV
7.
Using the analytical method, determine the centre of gravity of the plane uniform lamina shown in Fig.8.
Fig.8
15M
8.

Determine the y-coordinate of centroid of the triangular area of base b and height h from first principles.
6M

Locate the centroids of the following area shown in Fig.9.
Fig.9
9M
Unit V
9.

State and prove parallel axis theorem.
8M

Find the moment of inertia of the section shown in Fig.10 about horizontal centroidal axis and also find the radius of gyration about the same axis:
Fig.10
7M
Cont…4
4
10.
Determine the second moment of the area about the horizontal centroidal axis as shown in Fig.11. Also find radius of gyration.
Fig.11
15M