## Topic outline

• ### Motion and Measurement of Distances

##### Q38. Explain different types of motion. Write few example of each.

Ans. Types of motion:

Rectilinear motion – Motion along a straight path is called rectilinear motion. Example - motion of a vehicle on a straight road, march-past of soldiers in a parade or the falling of a stone.

Circular or Rotational motion – Motion along a curved path is called circular or rotational motion. Example: The motion of a point marked on the blade of an electric fan or the hands of a clock, moving wheel of a moving car.

Periodic motion – Motion that repeats after equal time interval is called periodic motion. Example: Motion of a pendulum, a branch of a tree moving to and fro, motion of a child on a swing, strings of a guitar or the surface of drums (tabla) being played.

##### Q39. What type of motion do the following objects have?

i.        the galloping of a horse – Linear motion/Rectilinear motion

ii.        the needle of sewing machine – Periodic motion

iii.        child sitting in a moving giant wheel – Circular and Periodic motion

iv.        surface of a drum being played - Periodic motion

v.        an artificial satellite orbiting the Earth at a constant height - Circular motion

vi.        soldiers in a march past - Linear motion/Rectilinear motion

vii.        an athlete on a circular track with a uniform speed - Circular motion

viii.        a rocking chair - Periodic motion

ix.        a stone which is tied to a rope and is being swung in circles - Circular motion

x.        a bouncing ball - Periodic motion

xi.        a girl walking on a straight road - Linear motion/Rectilinear motion

xii.        rotating blades of a helicopter - Circular motion

xiii.        the movements of a mosquito – Random motion

xiv.        the blades of an electric fan – Circular motion

xv.        a swing in motion - Periodic motion

xvi.        wheels of a moving car – Linear and Rotational motion

xvii.        movement of a marry-go round - Circular motion

xviii.        smoke from chimney – Random motion

xix.        a vibrating tuning fork - Periodic motion

xx.        bullet train on a straight track - Linear motion/Rectilinear motion

xxi.        motion of earth around sun - Circular and Periodic motion