JAMB and WAEC Physics questions: Friction

18 questions with answers and explanations. Tap an option to check yourself.

1. Question 1· Friction· JAMB

   A box presses on the floor with a normal reaction of 50 N. If the coefficient of friction is 0.4, find the limiting friction.

   • A20 N
   • B125 N
   • C50.4 N
   • D12.5 N

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2. Question 2· Friction· JAMB

   Compared with the limiting (static) friction between two surfaces, the kinetic (sliding) friction is

   • Azero
   • Bgreater
   • Cequal
   • Dsmaller

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3. Question 3· Friction· JAMB

   A 20 kg box is pulled across a level floor at constant speed by a horizontal force of 60 N. Find the coefficient of kinetic friction. [g = 10 m/s²]

   • A0.6
   • B3.3
   • C0.3
   • D1.2

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4. Question 4· Friction· JAMB

   A 5 kg block is pulled along a floor by a horizontal force of 30 N against a friction force of 10 N. Find its acceleration.

   • A2 m/s²
   • B6 m/s²
   • C4 m/s²
   • D8 m/s²

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5. Question 5· Friction· WAEC

   Friction is useful in

   • Aproducing unwanted heat
   • Bwearing out machine parts
   • Cwalking and braking
   • Dreducing efficiency

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6. Question 6· Friction· WAEC

   Which of these increases friction between two surfaces?

   • Aoiling the surfaces
   • Broughening the surfaces
   • Cusing ball bearings
   • Dstreamlining

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7. Question 7· Friction· WAEC

   A horizontal force of 80 N keeps a 20 kg box moving steadily along a floor. Find the coefficient of friction. (g = 10 m/s²)

   • A0.4
   • B4
   • C0.25
   • D2.5

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8. Question 8· Friction· JAMB

   A block of weight 40 N on a horizontal surface just starts to move when a horizontal force of 12 N is applied. Find the coefficient of static friction.

   • A28
   • B3.3
   • C0.48
   • D0.3

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9. Question 9· Friction· WAEC

   Friction is useful because it

   • Awears out machine parts
   • Ballows the brakes of a car to work
   • Cproduces unwanted heat
   • Dwastes energy

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10. Question 10· Friction· JAMB

    Ball bearings reduce friction because

    • Athey add weight
    • Bthey increase the normal reaction
    • Cthey make surfaces rough
    • Drolling friction is less than sliding friction

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11. Question 11· Friction· JAMB

    A block just begins to slide down a plane inclined at angle θ to the horizontal. The coefficient of static friction is

    • Atan θ
    • Bsin θ
    • Ccos θ
    • D1/tan θ

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12. Question 12· Friction· WAEC

    Which of the following reduces friction between moving parts of a machine?

    • ALubrication
    • BRoughening the surfaces
    • CIncreasing the load
    • DUsing sand

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13. Question 13· Friction· WAEC

    Which of these reduces friction between moving parts?

    • Aremoving the ball bearings
    • Broughening the surfaces
    • Cincreasing the normal reaction
    • Dlubricating them with oil

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14. Question 14· Friction· WAEC

    The friction acting on a body sliding over a surface is usually

    • Azero
    • Bgreater than the limiting friction
    • Cequal to its weight
    • Dless than the limiting friction

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15. Question 15· Friction· WAEC

    A block of weight 50 N needs a horizontal force of 20 N to slide at constant speed. The coefficient of kinetic friction is

    • A2.5
    • B0.4
    • C0.2
    • D70

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16. Question 16· Friction· JAMB

    An advantage of friction is that it

    • Aslows down vehicles unnecessarily
    • Bcauses wear of machine parts
    • Cwastes energy as heat
    • Denables us to walk without slipping

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17. Question 17· Friction· JAMB

    Which of the following reduces friction between moving parts?

    • Aincreasing the normal reaction
    • Broughening the surfaces
    • Clubrication
    • Dremoving ball bearings

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18. Question 18· Friction· WAEC

    A horizontal force of 12 N just moves a block of weight 40 N on a level floor. Find the coefficient of static friction.

    • A28
    • B3.3
    • C0.48
    • D0.3

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    Explanation and discussion