JEE Main - Static, kinetic and rolling friction Online Test (MCQ Quiz)

1. What is the force that opposes motion or impending motion between surfaces in contact called?

A) Normal force B) Tension force C) Friction force D) Gravitational force

2. Which type of friction acts when there is no relative motion between the surfaces in contact?

A) Kinetic friction B) Static friction C) Rolling friction D) Fluid friction

3. What is the maximum value of static friction called?

A) Limiting friction B) Sliding friction C) Rolling friction D) Coefficient of static friction

4. Which type of friction acts when one surface slides over another?

A) Static friction B) Rolling friction C) Kinetic friction D) Adhesive friction

5. What is the relationship between the kinetic friction force and the normal force (N)?

A) f_k = μ_k N B) f_s = μ_s N C) f_r = μ_r N D) f_k = N / μ_k

6. The coefficient of static friction (μ_s) is generally related to the coefficient of kinetic friction (μ_k) as:

A) μ_s > μ_k B) μ_s < μ_k C) μ_s = μ_k D) μ_s ≥ μ_k

7. Which type of friction occurs when an object rolls over a surface?

A) Static friction B) Kinetic friction C) Sliding friction D) Rolling friction

8. Rolling friction is typically much ______ than kinetic friction.

A) greater B) smaller C) equal D) variable

9. The force of static friction can vary from zero up to a maximum value.

A) True B) False C) Depends on the area of contact D) Depends on the velocity

10. If a block is at rest on a horizontal surface, the static friction force is:

A) Equal to the applied force B) Zero C) Equal to the limiting friction D) Equal to the coefficient of static friction

11. What is the primary cause of friction at the microscopic level?

A) Surface roughness and intermolecular attractions B) The gravitational pull between surfaces C) The magnetic properties of the materials D) The electrical charge on the surfaces

12. Which factor does NOT significantly affect the coefficient of kinetic friction for most dry surfaces?

A) The nature of the two surfaces in contact B) The normal force between the surfaces C) The velocity of sliding (at moderate speeds) D) The area of contact between the surfaces

13. When does kinetic friction become relevant?

A) When an object is at rest B) When an object is about to move C) When an object is in motion relative to a surface D) When an object is rolling

14. The coefficient of friction is a dimensionless quantity.

A) True B) False C) Only if the surfaces are identical D) Only for static friction

15. Consider a book resting on a table. If you push it gently and it doesn't move, the friction acting on it is:

A) Kinetic friction B) Limiting friction C) Static friction D) Rolling friction

16. If you push the same book harder and it starts to slide, the friction acting on it is now:

A) Static friction B) Limiting friction C) Kinetic friction D) Zero friction

17. What is the unit of the coefficient of friction?

A) Newton (N) B) Pascal (Pa) C) No unit (dimensionless) D) Meter per second squared (m/s²)

18. The force of rolling friction is approximately proportional to:

A) The normal force B) The coefficient of rolling friction and the normal force C) The inverse of the normal force D) The square of the normal force

19. A car tire rolling on a road experiences:

A) Pure sliding friction B) Pure rolling friction C) A combination of static and rolling friction D) No friction

20. Which of the following statements about friction is FALSE?

A) Friction opposes relative motion. B) The force of kinetic friction is generally constant. C) Static friction can be zero. D) Friction is a conservative force.

21. If the coefficient of static friction between a block and a surface is 0.5, and the mass of the block is 10 kg, what is the maximum static friction force?

A) 5 N B) 50 N C) 98 N D) 49 N

22. A wooden block is pushed across a horizontal wooden table. If the normal force is doubled by placing another identical block on top, how does the kinetic friction change?

A) It doubles B) It halves C) It remains the same D) It increases by a factor of four

23. What is the main advantage of rolling friction over sliding friction in applications like wheels?

A) It provides better grip. B) It is significantly smaller, reducing energy loss. C) It is easier to control. D) It generates more heat.

24. The term 'limiting friction' refers to:

A) The friction when an object is at rest. B) The friction when an object is sliding. C) The maximum possible static friction force. D) The friction that prevents an object from starting to roll.

25. Which of the following has the highest coefficient of rolling friction?

A) Steel ball on steel B) Rubber tire on asphalt C) Wooden wheel on wooden track D) Steel ball on ice

26. If a block is placed on an inclined plane, the static friction force acts:

A) Up the incline B) Down the incline C) Perpendicular to the incline D) Parallel to the normal force

27. When the angle of inclination of a plane is gradually increased, the block starts to slide when the angle equals:

A) The angle of repose B) The angle of kinetic friction C) The angle of static friction D) The angle of rolling friction

28. The angle of repose (θ) is related to the coefficient of static friction (μ_s) by:

A) μ_s = sin θ B) μ_s = cos θ C) μ_s = tan θ D) μ_s = θ

29. Friction is a non-conservative force because:

A) It depends on the path taken. B) It converts mechanical energy into heat. C) It is always present. D) It depends on velocity.

30. If a force F is applied to a block at rest, and the static friction force is f_s, the net force on the block is:

A) F B) f_s C) F - f_s D) F + f_s

31. What happens to the force of static friction if the applied force is less than the limiting friction?

A) It equals the applied force. B) It equals the limiting friction. C) It becomes zero. D) It becomes negative.

32. Which statement about friction between surfaces is most accurate?

A) It is directly proportional to the area of contact. B) It is independent of the relative velocity at high speeds. C) It depends on the microscopic irregularities of the surfaces. D) It is a conservative force.

33. A sled is being pulled at a constant velocity across snow. The friction acting on the sled is:

A) Static friction B) Limiting friction C) Kinetic friction D) Rolling friction

34. The coefficient of kinetic friction between rubber tires and dry asphalt is typically around:

A) 0.01 B) 0.1 C) 0.7 D) 2.0

35. What is the phenomenon where friction causes heat generation at the point of contact?

A) Adhesion B) Deformation C) Triboelectric effect D) Tribology

36. When an object is placed on a surface, the intermolecular forces between the atoms of the two surfaces contribute to:

A) Normal force B) Tension C) Friction D) Buoyancy

37. The force required to start moving a stationary object is greater than the force required to keep it moving at a constant velocity because:

A) Kinetic friction is greater than static friction. B) Static friction is greater than kinetic friction. C) The mass increases when the object starts moving. D) Air resistance is higher at the start.

38. Consider a sphere rolling down an inclined plane without slipping. The friction acting between the sphere and the plane is:

A) Kinetic friction B) Static friction C) Zero friction D) Viscous friction

39. If the coefficient of static friction between two surfaces is μ_s, the minimum horizontal force required to start moving a block of mass m on a horizontal surface is:

A) μ_s mg B) mg C) (μ_s / mg) D) 0

40. Which of the following is a method to reduce friction?

A) Increasing surface roughness B) Using lubricants C) Increasing the normal force D) Using materials with higher coefficients of friction

41. Lubricants reduce friction primarily by:

A) Increasing the normal force B) Reducing the intermolecular attraction between surfaces C) Creating a thicker boundary layer D) Increasing surface area

42. Friction is essential for:

A) Making objects move faster B) Preventing objects from moving C) Walking and braking of vehicles D) Reducing energy consumption

43. When a fluid (liquid or gas) opposes the motion of an object moving through it, this is called:

A) Static friction B) Kinetic friction C) Rolling friction D) Fluid friction (or drag)

44. The force of kinetic friction between two surfaces is independent of the velocity, provided the velocity is not too high.

A) True B) False C) Only for smooth surfaces D) Only for rough surfaces

45. If a block of mass 5 kg is at rest on a horizontal surface and the coefficient of static friction is 0.4, what is the minimum force required to start moving it?

A) 2 N B) 19.6 N C) 49 N D) 0 N

46. A block slides down an inclined plane with kinetic friction. If the coefficient of kinetic friction is μ_k, the frictional force is:

A) μ_k mg cos θ B) μ_k mg sin θ C) mg sin θ D) μ_k mg

47. What is the nature of friction when a car's brakes are applied, and the wheels are locked?

A) Static friction B) Kinetic friction C) Rolling friction D) Adhesive friction

48. When a car's anti-lock braking system (ABS) is active, it aims to keep the friction between the tires and the road as close as possible to:

A) Zero kinetic friction B) The maximum static friction C) The minimum kinetic friction D) The rolling friction limit

49. The reason why a heavier object experiences more friction than a lighter object (assuming same materials) is:

A) It has a larger area of contact. B) It has a greater normal force, leading to greater interlocking of surface irregularities. C) Its molecules are more attracted to the surface. D) Its velocity is lower.

50. Which type of friction is most relevant when pushing a box across a floor that is slightly uneven?

A) Pure static friction B) Pure kinetic friction C) Pure rolling friction D) Sliding friction with some deformation

Static, kinetic and rolling friction - Online Test

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