DEPARTMENT OF CIVIL ENGINEERING
National Institute of Technology Rourkela
End-Semester Examination, Autumn 2019-20
CE 1000: Engineering Mechanics
Class: Undergraduate
Duration: 3 hrs
Max. Marks: 50
Instructions: (1) Answer all questions.
(3) Assume any missing data after stating it clearly.
(4) Provide neat sketches wherever necessary
1. Determine the forces in the three members 1, 2 and 3 of the truss shown in Fig. 1
[7]
2. Find the value of moment M that should be applied to crank CD considering the equilibrium position of
the mechanism shown in Fig. 2. The block D is pinned to crank CD and is free to slide along AB. Use
the principle of virtual work to solve the problem.
[7]
1
2
3
6@4m = 24m
Fig. 2
Fig. 1
3. The 0.5 kg cylinder A is released from rest from the position shown and drops the distance h1 = 0.6 m
(refer Fig. 3). It then collides with the 0.4 kg block B; the coefficient of restitution is e = 0.8. Determine
the maximum downward displacement h2 of block B. Neglect all friction and assume that block B is
initially held in place by a hidden mechanism until the collision begins. The two springs of modulus k =
500 N/m are initially unstretched, and the distance d = 0.8 m.
[8]
4. Three identical discs A, B, and C rest on a smooth horizontal plane as shown in Fig. 4. The disk A is set
in motion with velocity V = 100 m/s after which it experiences a collision with discs B and C. The
coefficient of restitution e = 2/3. The angle α =300 is the angle between horizontal and the line joining
the centres of disk A and disk B at the time of impact. By symmetry, the line joining centres of disk A
and disk C makes similar angle α with the horizontal. Find the velocity of the three bodies after
impact.
[7]
Fig. 3
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Fig. 4
5. A 60 kg skateboard coasts down the circular track of radius 4 m as shown in Fig. 5. If it starts from rest
when the  = 00, determine the magnitude of normal reaction, the track exerts on it when  = 600. [7]
6. A 5 kg slender rod AB of 1 m length is pinned at A and initially is at rest. If a bullet of mass 10 gm is
fired into the rod at the center of percussion, P of the rod with a velocity of 400 m/s as shown in Fig. 6,
determine the angular velocity of the rod just after the bullet is embedded in it. Also calculate the
maximum angle θ through which the rod will swing after the impact.
[7]
7. Two uniform slender bars OA and BC showed in Fig. 7 has a mass of 8 kg and 4 kg, respectively. The
bars are welded at ‘A’ to form a T-shaped member and are rotating freely about a horizontal axis through
‘O.’ If it is released from rest while in the position shown, determine horizontal and vertical components
of the reaction at the pin ‘O’ as it passes the vertical position (1200 after release). Assume b = 1 m. [7]
B
A
4m

A
1m
400 m/s
30
P
Fig. 5
C
0
B
Fig. 7
Fig. 6
……
……
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