Un élève a représenté les positions successives occupées par un point en
mouvement toutes les \( 0,10s \). Malheureusement, son tracé est incomplet.
{"graphInit": {"range": [[-16.0, 136.0], [-6.4, 54.4]], "scale": [1.9736842105263157, 4.934210526315789], "axisArrows": "->", "axisOpacity": 0.5, "gridOpacity": 0.1, "gridStep": [8, 8], "tickStep": [1, 1], "labelStep": [136.0, 54.4], "unityLabels": true, "xLabel": "\\( x(cm) \\)", "yLabel": "\\( y(cm) \\)"}, "label": [[[8, 0], "A", "below"], [[-6.800000000000001, 8], "A", "center"], [[20.0, 8], 1, "above"], [[40.0, 16], 2, "above"], [[60.0, 24], 3, "above"], [[80.0, 32], 4, "above"], [[100.0, 40], 5, "above"], [[120.0, 48], 6, "above"]], "path": [[[[18.64, 7.4559999999999995], [21.36, 8.544]]], [[[18.64, 8.544], [21.36, 7.4559999999999995]]], [[[38.64, 15.456], [41.36, 16.544]]], [[[38.64, 16.544], [41.36, 15.456]]], [[[58.64, 23.456], [61.36, 24.544]]], [[[58.64, 24.544], [61.36, 23.456]]], [[[78.64, 31.456], [81.36, 32.544]]], [[[78.64, 32.544], [81.36, 31.456]]], [[[98.64, 39.456], [101.36, 40.544]]], [[[98.64, 40.544], [101.36, 39.456]]], [[[118.64, 47.456], [121.36, 48.544]]], [[[118.64, 48.544], [121.36, 47.456]]]]}
Le premier point a pour coordonnées \( (20\:;\:8) \) et le dernier
\( (120\:;\:48) \).
Déterminer la valeur de \( A \) servant à indiquer l'échelle du graphique.