• Example-01: Which of the following is true for displacement?
    (a) It cannot be zero.
    (b) Its magnitude is greater than the distance travelled by the object.

    Answer: None

     

    Example-02: Distinguish between speed and velocity.

    Answer: Speed has only magnitude while velocity has both magnitude and direction.

     

    Example-03: Under what condition(s) is the magnitude of average velocity of an object equal to its average speed?

    Answer: The magnitude of average velocity of an object will be equal to its average speed in the condition of uniform velocity.

     

    Example-04: What does the odometer of an automobile measure?

    Answer: In automobiles, odometer is used to measure the distance.

     

    Example-05: What is the quantity which is measured by the area occupied below the velocity-time graph?

    Answer: The quantity of distance is measured by the area occupied below the velocity time graph.

     

    Example-06: What does the path of an object look like when it is in uniform motion?

    Answer: In the case of uniform motion the path of an object will look like a straight line.

     

    Example-07: When will you say a body is in
    (i) uniform acceleration?
    (ii) non-uniform acceleration?

    Answer:

    (i) A body is said in uniform acceleration when its motion is along a straight line and its velocity changes by equal magnitude in equal interval of time.

    (ii) A body is said in non-uniform acceleration when its motion is along a straight line and its velocity changes by unequal magnitude in equal interval of time.

     

    Example-08: What is the nature of the distance-time graphs for uniform and non-uniform motion of an object?

    Answer:

    (a) The slope of the distance-time graph for an object in uniform motion is straight line.

    (b) The slope of the distance-time graph for an object in non-uniform motion is not a straight line.

     

    Example-09: What can you say about the motion of an object whose distance-time graph is a straight line parallel to the time axis?

    Answer: When the slope of distance-time graph is a straight line parallel to time axis, the object is moving with uniform motion.

     

    Example-10: What can you say about the motion of an object if its speed-time graph is a straight line parallel to the time axis?

    Answer: When the slope of a speed time graph is a straight line parallel to the time axis, the object is moving with uniform speed.

     

    Example-12: State which of the following situations are possible and give an example for each of these:

    (a) An object with a constant acceleration but with zero velocity

    (b) An object moving in a certain direction with an acceleration in the perpendicular direction.

     

    Answer:

    (a) The term acceleration implies that the velocity of the object is changing; inspite of that constant acceleration with zero velocity is impossible. When an object is thrown in upward direction, at the maximum height the velocity of the object becomes zero but still in that condition a constant acceleration due to gravity is working.


    (b) Object moving in a certain direction with an acceleration in perpendicular direction is possible; in case of circular motion. When an object moves on a circular path, its direction is along the tangent of the circle but acceleration is towards the radius of the circle. We know, that a tangent always makes a right angle with the radius; so when an object is in circular motion, the acceleration and velocity are in mutually perpendicular direction.