TRB BT Assistant - Friction, Equilibrium and Centre of Gravity One Line Questions & Answers

1. Which of the following is an example of static friction? — A book resting on a table

2. The center of gravity of a non-uniform rod is: — Closer to the heavier end

3. The condition for a body resting on a rough inclined plane to remain in equilibrium is that the angle of inclination (α) must be less than or equal to the: — Both angle of repose and angle of friction

4. The center of gravity of a body is the point where the resultant force of ______ acts. — Gravitational forces

5. If the coefficient of static friction is 0.6, what is the angle of repose? — Approximately 30.96 degrees

6. To keep a body in stable equilibrium, its center of gravity should be: — As low as possible

7. Where is the center of gravity of a uniform rod located? — At the center

8. For a uniform gravitational field, the center of gravity coincides with the: — Center of mass

9. The point where the entire weight of a body can be considered to act is called its: — Center of gravity

10. Friction is generally considered a ______ force. — Non-conservative

11. The coefficient of static friction (μ_s) is generally ______ the coefficient of kinetic friction (μ_k). — Greater than

12. If a block is pulled with a force F on a rough surface, and the block remains at rest, the friction is: — Equal to F

13. For an object to be in translational equilibrium, the vector sum of all forces acting on it must be: — Zero

14. A particle is in equilibrium if the resultant of all forces acting on it is: — Zero

15. What is the formula for the force of kinetic friction (f_k)? — f_k = μ_k N

16. Which of the following statements about friction is incorrect? — Friction is directly proportional to the applied force.

17. The center of gravity of a cone is located at a height of ______ from its base. — h/3

18. The center of gravity of a hollow sphere is at its: — Center

19. What happens to the center of gravity of a person standing on one leg compared to standing on two legs? — It is higher

20. A car is parked on a slope. The force preventing it from sliding down is: — Static friction

21. The maximum value of static friction is called: — Limiting friction

22. If a body is in equilibrium, its: — Linear momentum is constant

23. If a body is subjected to multiple forces and is in equilibrium, then the algebraic sum of the components of these forces along any direction is: — Zero

24. A uniform plank is supported at its ends. If a person walks along the plank, the condition for equilibrium requires that the total downward force must be balanced by the total upward force, and the net torque about any point must be: — Zero

25. What condition must be met for rotational equilibrium? — Net torque is zero

26. What is the unit of coefficient of friction? — Dimensionless

27. A body is in equilibrium under the action of three coplanar forces. If these forces are represented by the sides of a triangle taken in order, this is known as: — The triangle law of forces

28. The angle of friction (θ) is defined as the angle between the resultant force and the: — Normal reaction

29. A ladder leaning against a wall is in equilibrium if: — Both vertical and horizontal forces are balanced, and net torque is zero

30. The force of friction acts in a direction ______ to the applied force. — Opposite

31. When a body is pushed over a rough horizontal surface, the work done by friction is: — Negative

32. Consider a block on a horizontal surface. If the applied horizontal force is increased gradually, the friction force: — Increases up to the limiting value, then decreases

33. For a stable equilibrium, if the body is slightly displaced, its center of gravity: — Rises

34. In unstable equilibrium, if the body is slightly displaced, its center of gravity: — Falls

35. A body is in neutral equilibrium if, when slightly displaced, its center of gravity: — Remains at the same height

36. For a system to be in equilibrium, the net external force must be zero. This is a condition for: — Translational equilibrium

37. The friction between the surfaces of a tyre and the road is an example of: — Static friction

38. Which type of equilibrium is achieved when a ball is placed at the bottom of a hemispherical bowl? — Stable

39. If the applied force is less than the limiting friction, the object will: — Remain at rest

40. Which type of friction opposes motion when two surfaces are in relative motion? — Sliding friction

41. Which of the following conditions must be satisfied for a rigid body to be in equilibrium? — Sum of forces = 0 AND Sum of torques = 0

42. What is the angle of repose? — The maximum angle of inclination at which a body remains at rest.

43. Which factor does NOT affect the force of friction between two dry surfaces? — The relative velocity between the surfaces

44. Lami's Theorem applies to a system of ______ coplanar forces in equilibrium. — Three

45. A body is in equilibrium if it is either at rest or moving with: — Constant velocity

46. When is an object considered to be in equilibrium? — When the net force acting on it is zero

47. Rotational equilibrium occurs when the net torque acting on an object is: — Zero

48. If a body is in equilibrium, what is the net acceleration of the body? — Zero

49. The relationship between the angle of friction (θ) and the coefficient of static friction (μ_s) is: — μ_s = tan(θ)

Friction, Equilibrium and Centre of Gravity - One Line Questions