Un cube est posé sur un plan incliné et relié à un fil attaché à un poteau.
On représente ci-dessous la situation :
{"init": {"range": [[-7.0, 7.0], [-3.0, 12.0]], "scale": [20, 20]}, "line": [[[-6.0, -2.0], [6.0, -2.0], {"subtype": "segment", "stroke": "#ccc"}], [[-6.0, -1.0], [6.0, -1.0], {"subtype": "segment", "stroke": "#ccc"}], [[-6.0, 0.0], [6.0, 0.0], {"subtype": "segment", "stroke": "#ccc"}], [[-6.0, 1.0], [6.0, 1.0], {"subtype": "segment", "stroke": "#ccc"}], [[-6.0, 2.0], [6.0, 2.0], {"subtype": "segment", "stroke": "#ccc"}], [[-6.0, 3.0], [6.0, 3.0], {"subtype": "segment", "stroke": "#ccc"}], [[-6.0, 4.0], [6.0, 4.0], {"subtype": "segment", "stroke": "#ccc"}], [[-6.0, 5.0], [6.0, 5.0], {"subtype": "segment", "stroke": "#ccc"}], [[-6.0, 6.0], [6.0, 6.0], {"subtype": "segment", "stroke": "#ccc"}], [[-6.0, 7.0], [6.0, 7.0], {"subtype": "segment", "stroke": "#ccc"}], [[-6.0, 8.0], [6.0, 8.0], {"subtype": "segment", "stroke": "#ccc"}], [[-6.0, 9.0], [6.0, 9.0], {"subtype": "segment", "stroke": "#ccc"}], [[-6.0, 10.0], [6.0, 10.0], {"subtype": "segment", "stroke": "#ccc"}], [[-6.0, 11.0], [6.0, 11.0], {"subtype": "segment", "stroke": "#ccc"}], [[-6.0, -2.0], [-6.0, 11.0], {"subtype": "segment", "stroke": "#ccc"}], [[-5.0, -2.0], [-5.0, 11.0], {"subtype": "segment", "stroke": "#ccc"}], [[-4.0, -2.0], [-4.0, 11.0], {"subtype": "segment", "stroke": "#ccc"}], [[-3.0, -2.0], [-3.0, 11.0], {"subtype": "segment", "stroke": "#ccc"}], [[-2.0, -2.0], [-2.0, 11.0], {"subtype": "segment", "stroke": "#ccc"}], [[-1.0, -2.0], [-1.0, 11.0], {"subtype": "segment", "stroke": "#ccc"}], [[0.0, -2.0], [0.0, 11.0], {"subtype": "segment", "stroke": "#ccc"}], [[1.0, -2.0], [1.0, 11.0], {"subtype": "segment", "stroke": "#ccc"}], [[2.0, -2.0], [2.0, 11.0], {"subtype": "segment", "stroke": "#ccc"}], [[3.0, -2.0], [3.0, 11.0], {"subtype": "segment", "stroke": "#ccc"}], [[4.0, -2.0], [4.0, 11.0], {"subtype": "segment", "stroke": "#ccc"}], [[5.0, -2.0], [5.0, 11.0], {"subtype": "segment", "stroke": "#ccc"}], [[6.0, -2.0], [6.0, 11.0], {"subtype": "segment", "stroke": "#ccc"}], [[-1.0606601717798214, 5.060660171779821], [1.1102230246251565e-16, 6.121320343559643], {"subtype": "segment"}], [[1.1102230246251565e-16, 6.121320343559643], [2.1213203435596424, 4.0], {"subtype": "segment"}], [[2.1213203435596424, 4.0], [1.0606601717798214, 2.9393398282201786], {"subtype": "segment"}], [[-4.0, 9.060660171779821], [-0.5303300858899107, 5.590990257669732], {"subtype": "segment"}], [[-4.0, 8.0], [-4.0, 10.0], {"subtype": "segment"}], [[4.0, 0.0], [-4.0, 8.0], {"subtype": "segment"}], [[-4.0, 0.0], [4.0, 0.0], {"subtype": "segment"}]], "arc": [[[4.0, 0.0], [1.5, 1.5], 135.0, 180.0, false, {}]], "circle": [[[0.5303300858899106, 4.5303300858899105], 0.1, {"fill": "black"}]], "label": [[[2.0, -0.5], "\\alpha", "above", {}], [[0.030330085889910596, 4.0303300858899105], "G", "above", {}]]}
On considère à présent le solide comme un point pour effectuer le bilan des forces.
On représente la situation ci-dessous :
{"init": {"range": [[-5.0, 5.0], [-7.0, 5.0]], "scale": [40, 40]}, "line": [[[-4.0, -6.0], [4.0, -6.0], {"subtype": "segment", "stroke": "#ccc"}], [[-4.0, -5.0], [4.0, -5.0], {"subtype": "segment", "stroke": "#ccc"}], [[-4.0, -4.0], [4.0, -4.0], {"subtype": "segment", "stroke": "#ccc"}], [[-4.0, -3.0], [4.0, -3.0], {"subtype": "segment", "stroke": "#ccc"}], [[-4.0, -2.0], [4.0, -2.0], {"subtype": "segment", "stroke": "#ccc"}], [[-4.0, -1.0], [4.0, -1.0], {"subtype": "segment", "stroke": "#ccc"}], [[-4.0, 0.0], [4.0, 0.0], {"subtype": "segment", "stroke": "#ccc"}], [[-4.0, 1.0], [4.0, 1.0], {"subtype": "segment", "stroke": "#ccc"}], [[-4.0, 2.0], [4.0, 2.0], {"subtype": "segment", "stroke": "#ccc"}], [[-4.0, 3.0], [4.0, 3.0], {"subtype": "segment", "stroke": "#ccc"}], [[-4.0, 4.0], [4.0, 4.0], {"subtype": "segment", "stroke": "#ccc"}], [[-4.0, -6.0], [-4.0, 4.0], {"subtype": "segment", "stroke": "#ccc"}], [[-3.0, -6.0], [-3.0, 4.0], {"subtype": "segment", "stroke": "#ccc"}], [[-2.0, -6.0], [-2.0, 4.0], {"subtype": "segment", "stroke": "#ccc"}], [[-1.0, -6.0], [-1.0, 4.0], {"subtype": "segment", "stroke": "#ccc"}], [[0.0, -6.0], [0.0, 4.0], {"subtype": "segment", "stroke": "#ccc"}], [[1.0, -6.0], [1.0, 4.0], {"subtype": "segment", "stroke": "#ccc"}], [[2.0, -6.0], [2.0, 4.0], {"subtype": "segment", "stroke": "#ccc"}], [[3.0, -6.0], [3.0, 4.0], {"subtype": "segment", "stroke": "#ccc"}], [[4.0, -6.0], [4.0, 4.0], {"subtype": "segment", "stroke": "#ccc"}], [[0.0, 0.0], [2.0, 2.0000000000000004], {"subtype": "segment", "arrow-end": "classic-wide-long"}], [[0.0, 0.0], [-2.0, 1.9999999999999996], {"subtype": "segment", "arrow-end": "classic-wide-long"}], [[0.0, 0.0], [0.0, -4.0], {"subtype": "segment", "arrow-end": "classic-wide-long"}]], "circle": [[[0.0, 0.0], 0.1, {"fill": "black"}]], "label": [[[0.0, 0.0], "G", "above", {}], [[1.4242640687119286, 0.5757359312880718], null], [[-1.4242640687119286, 0.5757359312880712], null], [[0.6, -2.0], null], [[1.0, -3.0], "\\overrightarrow{\\rm P}", "above", {}], [[4.0, 2.220446049250313e-16], "\\overrightarrow{\\rm R}", "above", {}], [[-0.5, 0.9999999999999998], "\\overrightarrow{\\rm T}", "above", {}]]}
Données
- - Accélération de la pesanteur : \( g = 9,81\:\text{m}\mathord{\cdot}\text{s}^{-2} \)
- - Masse du solide : \( m = 122\:\text{g} \)
En calculant graphiquement l'échelle des forces représentés, donner la valeur, en Newton (N), representée par 1
carreau.
On donnera la réponse avec \( 2 \) chiffres significatifs et suivie de l'unité qui convient.