ZIMFundi
Sign inJoin free

Topic 1 of 8 · Form 3

Physical quantities, measurement and motion

SI units and prefixes; measuring length (rule, micrometer, vernier calipers), volume (measuring cylinder, displacement), time (stopwatch – time many oscillations). Scalars (distance, speed, mass, energy) and vectors (displacement, velocity, force, acceleration); resultant of two vectors at right angles by calculation or scale drawing.

Notes for this topic 1 file, in order

Create a free account to download PDFs.

  1. PDFPhysical quantities, measurement and motion – Physics notes (Cambridge O Level)45.8 KB

Measurement

SI units and prefixes; measuring length (rule, micrometer, vernier calipers), volume (measuring cylinder, displacement), time (stopwatch – time many oscillations). Scalars (distance, speed, mass, energy) and vectors (displacement, velocity, force, acceleration); resultant of two vectors at right angles by calculation or scale drawing.

Motion

Speed = distance ÷ time; velocity is speed in a stated direction; acceleration a = Δv/Δt.

  • Distance–time graphs: gradient = speed.
  • Speed–time graphs: gradient = acceleration; area = distance.

Worked example: A cyclist accelerates uniformly from 2 m/s to 10 m/s in 4 s. Find the acceleration and distance.

a = 8 ÷ 4 = 2 m/s²; distance = average speed × time = 6 × 4 = 24 m

Free fall

Acceleration of free fall g ≈ 9.8 m/s² near the Earth's surface; with air resistance, objects reach terminal velocity.

Exam tip: Read graph scales carefully – most graph errors come from misreading axes.

Check yourself

  1. Is acceleration a scalar or a vector?
  2. Find the resultant of forces of 6 N east and 8 N north.
  3. What does a horizontal line on a speed–time graph show?
Show answers
  1. A vector.
  2. 10 N at 53° north of east (bearing 037°).
  3. Constant speed (zero acceleration).
Next topicForces, mass, weight, density and momentum

Questions about this topic (0)

No questions about this topic yet.