Kerala SSLC · Physics · Class 10

Motion and Force: Important Questions with Answers

These are 10 important multiple-choice questions from the Kerala SSLC Physics chapter “Motion and Force” (Kerala SCERT syllabus). Each one shows the correct answer and a short explanation of why it is right. Try answering before you read the answer. ExamSummary has 10 practice questions on this chapter in total.

  1. Q1.Which property of an object primarily determines its inertia?

    • A)Volume
    • B)Density
    • C)Mass
    • D)Shape

    Answer: C) Mass

    Inertia is the inherent property of an object to resist changes in its state of motion. It is directly proportional to the mass of the object, meaning heavier objects have greater inertia.

  2. Q2.What physical quantity is represented by the area under a velocity-time graph?

    • A)Acceleration
    • B)Distance
    • C)Displacement
    • D)Speed

    Answer: C) Displacement

    The area enclosed between the velocity-time graph and the time axis corresponds to the displacement of the body. While speed-time graphs give distance, velocity-time graphs specifically yield displacement.

  3. Q3.According to Newton's second law of motion, what is the rate of change of momentum equal to?

    • A)Mass
    • B)Acceleration
    • C)Force
    • D)Impulse

    Answer: C) Force

    Newton's second law states that the rate of change of momentum of a body is directly proportional to the applied unbalanced force. This relationship is mathematically expressed as Force = Rate of change of momentum.

  4. Q4.When two bodies collide in an isolated system, which physical quantity remains conserved?

    • A)Kinetic Energy
    • B)Linear Momentum
    • C)Potential Energy
    • D)Force

    Answer: B) Linear Momentum

    In the absence of external forces, the total linear momentum of a system remains constant before and after a collision. Kinetic energy is only conserved in elastic collisions, whereas momentum is conserved in all isolated collisions.

  5. Q5.In which direction does the force of kinetic friction act on a sliding object?

    • A)Same direction as motion
    • B)Opposite to the direction of motion
    • C)Perpendicular to the surface
    • D)Zero direction

    Answer: B) Opposite to the direction of motion

    Friction is a contact force that opposes the relative motion between two surfaces. Therefore, kinetic friction always acts in the direction opposite to the velocity of the moving object.

  6. Q6.A car is moving along a circular path with constant speed. Is the car accelerating?

    • A)Yes, due to centripetal acceleration
    • B)No, because speed is constant
    • C)Yes, due to tangential acceleration
    • D)No, because no force acts

    Answer: A) Yes, due to centripetal acceleration

    Even though the speed is constant, the direction of the velocity vector changes continuously in circular motion. This change in direction constitutes centripetal acceleration directed towards the center of the circle.

  7. Q7.Which equation of motion relates displacement (s), initial velocity (u), acceleration (a), and time (t)?

    • A)v = u + at
    • B)s = ut + 1/2at^2
    • C)v^2 - u^2 = 2as
    • D)F = ma

    Answer: B) s = ut + 1/2at^2

    The equation s = ut + 1/2at^2 is derived to calculate displacement when initial velocity, acceleration, and time are known. It excludes final velocity from the variables involved.

  8. Q8.If the net external force acting on a body is zero, what happens to its velocity?

    • A)It increases continuously
    • B)It decreases continuously
    • C)It remains constant
    • D)It becomes zero immediately

    Answer: C) It remains constant

    According to Newton's first law, if the net force is zero, the body continues in its state of rest or uniform motion. Consequently, the velocity does not change in magnitude or direction.

  9. Q9.What is the SI unit of momentum?

    • A)Newton (N)
    • B)kg m/s
    • C)Joule (J)
    • D)kg m/s^2

    Answer: B) kg m/s

    Momentum is the product of mass (kg) and velocity (m/s). Therefore, the resulting SI unit is kilogram meter per second (kg m/s). Newton is the unit for force, not momentum.

  10. Q10.Action and reaction forces described in Newton's third law act on...

    • A)The same body simultaneously
    • B)Two different bodies
    • C)One body sequentially
    • D)Neither of the bodies

    Answer: B) Two different bodies

    Action and reaction forces are interaction pairs between two distinct objects. Since they act on different bodies, they cannot cancel each other out to produce equilibrium on a single object.

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