Applied Mechanics Questions and Answers - Set 03 - ObjectiveBooks

# Practice Test: Question Set - 03

1. A rod 5 m in length is moving in a vertical plane. When it is inclined at 60° to horizontal, its lower end is moving horizontally at 3 m/sec and upper end is moving in vertical direction. The velocity of its upper end, is
(A) 0.5 m/sec
(B) 1.0 m/sec
(C) 1.5 m/sec
(D) 2.5 m/sec

2. A force P of 50 N and another force Q of unknown magnitude act at 90° to each other. They are balanced by a force of 130 N. The magnitude of Q is
(A) 60 N
(B) 80 N
(C) 100 N
(D) 120 N

3. On a mass ‘m’ describing a circular path of radius ‘r’, the centrifugal force
(A) Acts tangentially to the circular path
(B) Acts towards the centre of rotation
(C) Acts away from the centre of rotation
(D) Is mw2r/g kgf

4. Parallelogram Law of Forces states, "if two forces acting simultaneously on a particle be represented in magnitude and direction by two adjacent sides of a parallelogram, their resultant may be represented in magnitude and direction by
(A) Its longer side
(B) Its shorter side
(C) The diagonal of the parallelogram which does not pass through the point of intersection of the forces
(D) The diagonal of the parallelogram which passes through the point of intersection of the forces

5. The following factor affects the orbit of a satellite up to an altitude of 720 km from the earth's surface
(A) Uneven distribution of the gravitational field
(B) Gravity of the sun and the moon
(C) Aerodynamic forces
(D) None of these

6. Two circular discs of same weight and thickness are made from metals having different densities. Which disc will have the larger rotational inertia about its central axis?
(A) Disc with larger density
(B) Disc with smaller density
(C) Both discs will have same rotational inertia
(D) None of the above

7. Moment of inertia of a squares of side ‘b’ about an axis through its centre of gravity, is
(A) b3/4
(B) b4/12
(C) b4/3
(D) b4/8

8. The masses of two balls are in the ratio of 2 : 1 and their respective velocities are in the ratio of 1 : 2 but in opposite direction before impact. If the coefficient of restitution is ½, the velocities of separation of the balls will be equal to
(A) Original velocity in the same direction
(B) Half the original velocity in the same direction
(C) Half the original velocity in the opposite direction
(D) Original velocity in the opposite direction

9. The ratio of the reactions RA and RB of a simply supported beam shown in below figure is
(A) 0.50
(B) 0.40
(C) 0.67
(D) 1.00

10. A disc of mass 4 kg, radius 0.5 m and moment of inertia 3 kg.m² rolls on a horizontal surface so that its center moves with speed 5 m/see. Kinetic energy of the disc is
(A) 50 J
(B) 150 J
(C) 200 J
(D) 400 J

11. A point subjected to a number of forces will be in equilibrium, if
(A) Sum of resolved parts in any two directions at right angles, are both zero
(B) Algebraic sum of the forces is zero
(C) Two resolved parts in any two directions at right angles are equal
(D) Algebraic sum of the moments of the forces about the point is zero

12. The resultant of two forces ‘P’ and ‘Q’ acting at an angle ‘θ’, is
(A) P2 + Q2 + 2P sin θ
(B) P2 + Q2 + 2PQ cos θ
(C) P2 + Q2 + 2PQ tan θ
(D) √(P2 + Q2 + 2PQ cos θ)

13. A particle moves with a velocity of 2 m/sec in a straight line with a negative acceleration of 0.1 m/sec2. Time required to traverse a distance of 1.5 m, is
(A) 40 sec
(B) 30 sec
(C) 20 sec
(D) 15 sec

14. It is observed that in a certain sinusoidal oscillation, the amplitude is linearly dependent on the frequency f. If the maximum velocity during the oscillation is V, then V must be proportional to
(A) f
(B) 1/f
(C) 1/f²
(D) f²

15. One Joule is equivalent to
(A) 9.81 Newton metre
(B) 1 Newton metre
(C) 1 kg wt metre
(D) 1 dyne metre

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