CBSE · Class 9 · Science · Chapter 4

Describing Motion Around Us

Learn to describe motion using distance, displacement, speed, velocity, acceleration and motion graphs.

10 lessons 55 min
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Lessons in this chapter

  1. 1Motion in a Straight LineThe object moved, but first we need to agree on where zero lives.
  2. 2Distance travelled and displacementThe path took the scenic route while displacement chose the shortcut.
  3. 3Average speed and average velocitySpeed counts every step; velocity also asks which way you ended up.
  4. 4Average accelerationAcceleration is what turns a calm bus ride into an unexpected balance test.
  5. 5Graphical Representation of MotionMotion graphs let moving objects leave behind neat little stories.
  6. 6Position-time graphsA sloping line quietly tells you how fast position is changing.
  7. 7Velocity-time graphsThis graph gives velocity, acceleration and displacement without asking for overtime.
  8. 8Kinematic Equations for Motion in a Straight Line with Constant AccelerationThree equations walk into a road problem and only one leaves with the unknown.
  9. 9Motion in a PlaneGoing in circles keeps speed steady while velocity changes its mind.
  10. 10Chapter Summary and PracticeEvery formula returns for one final lap around the chapter.
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