3.2.11

Relative Motion

Test yourself

Relative Motion

Objects seem to move at different speeds depending on whether or not you yourself are moving. Have you ever looked out the window of a train, thinking you were leaving the platform, but it was another train moving instead?

Illustrative background for Relative motionIllustrative background for Relative motion ?? "content

Relative motion

  • Relative motion is the speed of something compared to the observer.
  • If you are in a car and go past people at a bus stop, you may not see them very well because you are moving and they are still.
  • If you overtake a motorbike in your car, and look at the rider, it may seem you spend longer going past them than the people at the bus stop.
Illustrative background for Calculating relative motionIllustrative background for Calculating relative motion ?? "content

Calculating relative motion

  • If two objects are moving in the same direction, the relative motion is:
    • Fastest speed - slowest speed.
  • If objects are moving towards each other (in opposite directions), the relative speed is:
    • Object 1's speed + object 2's speed.
  • This why a head-on collision is worse.
Illustrative background for Relative motion - train calculationIllustrative background for Relative motion - train calculation ?? "content

Relative motion - train calculation

  • A train that travels at 50m/s from the East is heading towards a train that is traveling at 70m/s from the west. What is the relative motion?
    • 50+70 = 120m/s.

Jump to other topics

1Biology

1.1Cells, Tissues & Organs

1.2Reproduction & Variation

1.3Ecological Relationships & Classification

1.4Digestion & Nutrition

1.5Plants & Photosynthesis

1.6Biological Systems & Processes

2Chemistry

2.1Particles

2.2Chemical Reactions

2.3Atoms, Elements, Compounds

2.4The Periodic Table

2.5Materials & the Earth

2.6Reactivity

2.7Energetics

2.8Properties of Materials

3Physics

3.1Energy

3.2Forces & Motion

3.3Waves

3.4Electricity & Magnetism

3.5Matter

3.6Space Physics

4Thinking Scientifically

Go student ad image

Unlock your full potential with GoStudent tutoring

  • Affordable 1:1 tutoring from the comfort of your home

  • Tutors are matched to your specific learning needs

  • 30+ school subjects covered

Book a free trial lesson