IGCSE›Cambridge IGCSE Physics›Mind mapsMotionCambridge IGCSE Physics: Mind mapStudy pack PDFAlso for this subtopic:Revision notesFlashcardsSubtopic testCover factsSpeed and velocitySpeed is scalar: distance per unit timeVelocity is a vector: speed with directionv=stv = \frac{s}{t}v=tsAverage speed = total distance ÷ total timeDistance-time graphsHorizontal line means at restStraight line means constant speedGradient = speedCurved line means speed is changingSpeed-time graphsGradient = accelerationArea under line = distance travelledHorizontal line means constant speedDownward slope means decelerationMotionspeed, velocity, accelerationm/sm/s²sAccelerationChange in velocity per unit timea=ΔvΔta = \frac{\Delta v}{\Delta t}a=ΔtΔvΔv\Delta vΔv = final − initial velocityNegative acceleration = decelerationFallingNo resistance: constant g=9.8 m/s2g = 9.8\,\text{m/s}^2g=9.8m/s2Resistance increases with speedTerminal velocity: air resistance = weightResultant force zero, so acceleration is zeroExam tipsVelocity needs direction, speed does notUpward slope on speed-time = acceleratingCheck if graph line is straight or curvedTrapezium area: 12(v1+v2)t\frac{1}{2}(v_1+v_2)t21(v1+v2)t