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MASTERS ACADEMIA CENTRE, ENGINEERIING MECHANICS QUESTIONS -1, 1. The relation between coefficient of friction and angle of friction is, (A) = tan , (B) = sin , (C) = cos (D) = cot , 2. A ladder is resting on a smooth ground and is leaning against a vertical wall., The frictional force developed at the point of contact of ladder with the vertical, wall will be, a. Upwards at its upper end, b. Towards the wall at its upper end, c. Away the wall at its upper end, d. downwards at its upper end, 3. The friction experienced by a body, when in motion, is known as, a. rolling friction, b. dynamic friction, c. limiting friction, d. static friction, 4. Maximum value of the static friction is known as, a. Limiting friction, b. Sliding friction, c. Dry friction, d. Kinetic friction, 4. Angle, which the resultant R of normal reaction and limiting force of friction, makes with the normal reaction is, a) angle of repose, b) Angle of elevation, c) Angle of friction, d) None of the above, 5. The velocity ratio in case of an inclined plane inclined at angle θ to the, horizontal and weight being pulled up the inclined plane by vertical effort is, A., , sin θ, , LET 2021, , Page 1
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MASTERS ACADEMIA CENTRE, B., , cos θ, , C., , tan θ, , D., , cosec θ, , 6. The range of projectile on a downward inclined plane is __________ the range, on upward inclined plane for the same velocity of projection and angle of, projection., A., , less than, , B., , more than, , C., , equal to, , 7. A body of weight W is required to move up on rough inclined plane whose angle, of inclination with the horizontal is α. The effort applied parallel to the plane is, given by(where μ = tanφ = Coefficient of friction between the plane and the body.), A., , P = W tanα, , B., , P = W tan(α + φ), , C., , P = W (sinα + μcosα), , D., , P = W (cosα + μsinα), , 8. If the resultant of two equal forces has the same magnitude as either of the, forces, then the angle between the two forces is, A., , 30°, , B., , 60°, , C., , 90°, , D., , 120°, , 9. Moment of inertia of a circular section about an axis perpendicular to the section, is, A., , πd3/16, , LET 2021, , Page 2
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MASTERS ACADEMIA CENTRE, B., , πd3/32, , C., , πd4/32, , D., , πd4/64, , 10. The time of flight (t) of a projectile on an upward inclined plane is(where u =, Velocity of projection, α = Angle of projection, and β = Inclination of the plane, with the horizontal.), A., B., C., D., 11. The unit of angular acceleration is, A. N-m, B. m/s, C. m/s2, D. rad/s2, , 12. Moment of inertia of a triangular section of base (b) and height (h) about an, axis passing through its C.G. and parallel to the base, is, A. bh3/4, B. bh3/8, C. bh3/12, D. bh3/36, , 13. Which of the following is an equation of linear motion?(where, u and v = Initial, and final velocity of the body, a = Acceleration of the body, and s = Displacement, LET 2021, , Page 3
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MASTERS ACADEMIA CENTRE, of the body in time t seconds.), A. v = u + a.t, B. s = u.t + 1/2 a.t2, C. v2 = u2+2a.s, D. all of these, 14. If a number of forces are acting at a point, theirresultant will be inclined at an, angle θ with the horizontal, such that, A. tan θ = ∑H/∑V, B. tan θ = ∑V/∑H, C. tan θ = ∑Vx∑H, D., Answer: Option B, 15., , The above figure shows the two equal forces at right angles acting at a point. The, value of force R acting along their bisector and in opposite direction is, A. P/2, B. 2P, C., D., Answer: Option C, 16. The force required to move the body up the plane will be minimum if it makes, LET 2021, , Page 4
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MASTERS ACADEMIA CENTRE, an angle with the inclined plane __________ the angle of friction., A. equal to, B. less than, C. greater than, Answer: Option A, , 17. The frequency of oscillation of a torsional pendulum is, A., B., C., D., Answer: Option D, 18. The range of a projectile is maximum, when the angle of projection is, A. 30°, B. 45°, C. 60°, D. 90°, Answer: Option B, 19. Static friction is always __________ dynamic friction., A. equal to, B. less than, C. greater than, Answer: Option C, LET 2021, , Page 5
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MASTERS ACADEMIA CENTRE, 20. A body will begin to move down an inclined plane if the angle of inclination of, the plane is __________ the angle of friction., A. equal to, B. less than, C. greater than, Answer: Option C, 21. The maximum frictional force, which comes into play, when a body just begins, to slide over the surface of the other body, is known as, A. static friction, B. dynamic friction, C. limiting friction, D. coefficient of friction, Answer: Option C, 22. The centre of gravity of an equilateral triangle with each side a, is __________, from any of the three sides., A. √3a/2, B. 2√3a, C. a/2√3, D. 3√2a, Answer: Option C, 23. The algebraic sum of the resolved parts of a number of forces in a given, direction is equal to the resolved part of their resultant in the same direction. This, is known as, A. principle of independence of forces, B. principle of resolution of forces, , LET 2021, , Page 6
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MASTERS ACADEMIA CENTRE, C. principle of transmissibility of forces, D. none of these, Answer: Option B, 24. The angle between two forces when the resultant is maximum and minimum, respectively are, A. 0° and 180°, B. 180° and 0°, C. 90° and 180°, D. 90° and 0°, Answer: Option A, 25. When a rigid body is suspended vertically, and it oscillates with a small, amplitude under the action of the force of gravity, the body is known as, A. simple pendulum, B. compound pendulum, C. torsional pendulum, D. second's pendulum, Answer: Option B, 26. Moment of inertia of a hollow circular section, as shown in the below figure, about X-axis, is, , LET 2021, , Page 7
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MASTERS ACADEMIA CENTRE, , A., B., C., D., Answer: Option D, , 27. two like parallel forces are acting at a distance of 24 mm apart and their, resultant is 20 N. It the line of action of the resultant is 6 mm from any given force,, the two forces are, A. 15 N and 5 N, B. 20 N and 5 N, C. 15 N and 15 N, D. none of these, Answer: Option A, , 28. If two bodies having masses m1 and m2 (m1>m2) have equal kinetic energies,, LET 2021, , Page 8
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MASTERS ACADEMIA CENTRE, the momentum of body having mass m1 is __________ the momentum of body, having mass m2., A. equal to, B. less than, C. greater than, Answer: Option C, , LET 2021, , Page 9
