IB›IB Physics SL›Mind mapsA.1 KinematicsIB Physics SL: Mind mapStudy pack PDFAlso for this subtopic:Revision notesFlashcardsSubtopic testCover factsDistance or displacementDisplacement: change in position, a vectorDistance: total path length, a scalarFull lap of track: distance 400 m, displacement zeroDistance never decreases or goes negativeVelocity and accelerationVelocity = displacement ÷ time; speed is its magnitudeAcceleration = change in velocity ÷ timeInstantaneous value: gradient of the tangentArea under v–t graph = displacementGradient of v–t graph = accelerationUniform accelerationv=u+atv = u + atv=u+ats=ut+12at2s = ut + \frac{1}{2}at^2s=ut+21at2v2=u2+2asv^2 = u^2 + 2asv2=u2+2ass=u+v2ts = \frac{u + v}{2}ts=2u+vtGive every vector a sign; pick one positive directionKinematicsdescribing motionsuvatProjectilesHorizontal: constant velocity, x=uxtx = u_x tx=uxtVertical: uniform acceleration g downwardsComponents linked only by timeAt the top, vertical velocity is zero, horizontal is notLevel ground: time of flight 2uy/g2u_y/g2uy/gDragDrag acts opposite to velocity, grows with speedReduces range and maximum heightPath becomes asymmetric, steeper on descentFalling body reaches terminal speed when drag = weightExam tipsVelocity changing unevenly in equal times means non-uniformSuvat equations are invalid for non-uniform accelerationUse trapezium area method for non-uniform displacementSpeed at top of trajectory is not zero