What this covers
This standard sits within Force and Motion I. In a one-to-one lesson we make sure the idea is clear first, then move straight to applying it in the exact way SPM asks, with correct units and full working.
Formulas you may need
How it is examined
It can appear in Paper 1 (objective) and Paper 2 (structured), and where an experiment applies, in Paper 3. We do not predict which questions appear; we prepare the technique for all of them.
A common mistake
How to study it
Learn the definition precisely, practise one or two SPM-style questions with full working, and link it to the rest of Force and Motion I. If it keeps costing marks, a one-to-one lesson fixes exactly that.
Force and Motion I · Formulas · Exam Papers
What you need to know
Linear motion describes movement along a straight line and is built on a set of precisely defined quantities. Distance is the total path length travelled, a scalar measured in metres (m), while displacement is the straight-line distance from the starting point to the final point in a specified direction, a vector also measured in metres.
Speed is distance travelled per unit time, a scalar in m s⁻¹, while velocity is displacement per unit time, a vector in m s⁻¹. Acceleration is the rate of change of velocity, measured in m s⁻².
Four equations of motion apply when acceleration is constant: v = u + at, s = ut + ½at², v² = u² + 2as, and a = (v − u) / t, where u is initial velocity, v is final velocity, s is displacement, t is time and a is acceleration. For example, if a car starts from rest and reaches 20 m s⁻¹ in 4 s, its acceleration is a = (v − u) / t = (20 − 0) m s⁻¹ ÷ 4 s = 5 m s⁻².
A ticker-tape timer marks equal time intervals on a paper tape and is used in experiments to determine velocity and acceleration from the spacing between dots.
Worked example
Question: A motorcycle travelling at an initial velocity of 8 m s⁻¹ accelerates uniformly at 3 m s⁻² for 6 s. Calculate the final velocity and the distance travelled during this time.
Given: u = 8 m s⁻¹, a = 3 m s⁻², t = 6 s. Using v = u + at: v = 8 m s⁻¹ + (3 m s⁻² × 6 s) = 8 m s⁻¹ + 18 m s⁻¹ = 26 m s⁻¹.
Using s = ut + ½at²: s = (8 m s⁻¹ × 6 s) + ½ × 3 m s⁻² × (6 s)² = 48 m + (½ × 3 × 36) m = 48 m + 54 m = 102 m. The final velocity is 26 m s⁻¹ and the distance travelled is 102 m.
Note that every term in the formula must have consistent units before the terms are added together, which is why the answer for s is expressed in metres throughout.
How it is examined
Paper 1 objective items test whether candidates can distinguish distance from displacement and speed from velocity, and can select the correct equation of motion for a given scenario. Paper 2 structured and essay questions commonly require candidates to calculate an unknown quantity using an equation of motion, showing the substitution and the final answer with units, or to describe how a ticker-tape timer is used to find velocity and acceleration.
Paper 3 practical questions may involve a trolley on a runway with a ticker-tape timer, where candidates measure tape lengths to calculate velocity at different points.
Common mistakes include mixing up u and v, using an equation that does not match the given quantities, forgetting to square t in s = ut + ½at², and omitting units in the final answer. Since SPM Physics provides no formula sheet, all four equations of motion must be memorised precisely, including which variable is missing from each one, so that the correct equation can be selected quickly under exam conditions.
Source: DSKP KSSM Physics Form 4 and 5 (Versi English) (Bahagian Pembangunan Kurikulum (BPK), KPM)