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": [[-10.0, 10.0], [-3.0, 11.0]], "scale": [20, 20]}, "line": [[[-9.0, -2.0], [9.0, -2.0], {"subtype": "segment", "stroke": "#ccc"}], [[-9.0, -1.0], [9.0, -1.0], {"subtype": "segment", "stroke": "#ccc"}], [[-9.0, 0.0], [9.0, 0.0], {"subtype": "segment", "stroke": "#ccc"}], [[-9.0, 1.0], [9.0, 1.0], {"subtype": "segment", "stroke": "#ccc"}], [[-9.0, 2.0], [9.0, 2.0], {"subtype": "segment", "stroke": "#ccc"}], [[-9.0, 3.0], [9.0, 3.0], {"subtype": "segment", "stroke": "#ccc"}], [[-9.0, 4.0], [9.0, 4.0], {"subtype": "segment", "stroke": "#ccc"}], [[-9.0, 5.0], [9.0, 5.0], {"subtype": "segment", "stroke": "#ccc"}], [[-9.0, 6.0], [9.0, 6.0], {"subtype": "segment", "stroke": "#ccc"}], [[-9.0, 7.0], [9.0, 7.0], {"subtype": "segment", "stroke": "#ccc"}], [[-9.0, 8.0], [9.0, 8.0], {"subtype": "segment", "stroke": "#ccc"}], [[-9.0, 9.0], [9.0, 9.0], {"subtype": "segment", "stroke": "#ccc"}], [[-9.0, 10.0], [9.0, 10.0], {"subtype": "segment", "stroke": "#ccc"}], [[-9.0, -2.0], [-9.0, 10.0], {"subtype": "segment", "stroke": "#ccc"}], [[-8.0, -2.0], [-8.0, 10.0], {"subtype": "segment", "stroke": "#ccc"}], [[-7.0, -2.0], [-7.0, 10.0], {"subtype": "segment", "stroke": "#ccc"}], [[-6.0, -2.0], [-6.0, 10.0], {"subtype": "segment", "stroke": "#ccc"}], [[-5.0, -2.0], [-5.0, 10.0], {"subtype": "segment", "stroke": "#ccc"}], [[-4.0, -2.0], [-4.0, 10.0], {"subtype": "segment", "stroke": "#ccc"}], [[-3.0, -2.0], [-3.0, 10.0], {"subtype": "segment", "stroke": "#ccc"}], [[-2.0, -2.0], [-2.0, 10.0], {"subtype": "segment", "stroke": "#ccc"}], [[-1.0, -2.0], [-1.0, 10.0], {"subtype": "segment", "stroke": "#ccc"}], [[0.0, -2.0], [0.0, 10.0], {"subtype": "segment", "stroke": "#ccc"}], [[1.0, -2.0], [1.0, 10.0], {"subtype": "segment", "stroke": "#ccc"}], [[2.0, -2.0], [2.0, 10.0], {"subtype": "segment", "stroke": "#ccc"}], [[3.0, -2.0], [3.0, 10.0], {"subtype": "segment", "stroke": "#ccc"}], [[4.0, -2.0], [4.0, 10.0], {"subtype": "segment", "stroke": "#ccc"}], [[5.0, -2.0], [5.0, 10.0], {"subtype": "segment", "stroke": "#ccc"}], [[6.0, -2.0], [6.0, 10.0], {"subtype": "segment", "stroke": "#ccc"}], [[7.0, -2.0], [7.0, 10.0], {"subtype": "segment", "stroke": "#ccc"}], [[8.0, -2.0], [8.0, 10.0], {"subtype": "segment", "stroke": "#ccc"}], [[9.0, -2.0], [9.0, 10.0], {"subtype": "segment", "stroke": "#ccc"}], [[-1.3416407864998738, 4.170820393249937], [-0.6708203932499366, 5.512461179749811], {"subtype": "segment"}], [[-0.6708203932499366, 5.512461179749811], [2.0124611797498106, 4.170820393249937], {"subtype": "segment"}], [[2.0124611797498106, 4.170820393249937], [1.341640786499874, 2.8291796067500625], {"subtype": "segment"}], [[-7.0, 7.838525491562422], [-1.0062305898749053, 4.841640786499873], {"subtype": "segment"}], [[-7.0, 7.0], [-7.0, 9.0], {"subtype": "segment"}], [[7.0, 0.0], [-7.0, 7.0], {"subtype": "segment"}], [[-7.0, 0.0], [7.0, 0.0], {"subtype": "segment"}]], "arc": [[[7.0, 0.0], [1.5, 1.5], 153.434948822922, 180.0, false, {}]], "circle": [[[0.33541019662496846, 4.170820393249937], 0.1, {"fill": "black"}]], "label": [[[5.0, -0.5], "\\alpha", "above", {}], [[-0.16458980337503154, 3.6708203932499366], "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": [[-6.0, 6.0], [-12.0, 10.0]], "scale": [40, 40]}, "line": [[[-5.0, -11.0], [5.0, -11.0], {"subtype": "segment", "stroke": "#ccc"}], [[-5.0, -10.0], [5.0, -10.0], {"subtype": "segment", "stroke": "#ccc"}], [[-5.0, -9.0], [5.0, -9.0], {"subtype": "segment", "stroke": "#ccc"}], [[-5.0, -8.0], [5.0, -8.0], {"subtype": "segment", "stroke": "#ccc"}], [[-5.0, -7.0], [5.0, -7.0], {"subtype": "segment", "stroke": "#ccc"}], [[-5.0, -6.0], [5.0, -6.0], {"subtype": "segment", "stroke": "#ccc"}], [[-5.0, -5.0], [5.0, -5.0], {"subtype": "segment", "stroke": "#ccc"}], [[-5.0, -4.0], [5.0, -4.0], {"subtype": "segment", "stroke": "#ccc"}], [[-5.0, -3.0], [5.0, -3.0], {"subtype": "segment", "stroke": "#ccc"}], [[-5.0, -2.0], [5.0, -2.0], {"subtype": "segment", "stroke": "#ccc"}], [[-5.0, -1.0], [5.0, -1.0], {"subtype": "segment", "stroke": "#ccc"}], [[-5.0, 0.0], [5.0, 0.0], {"subtype": "segment", "stroke": "#ccc"}], [[-5.0, 1.0], [5.0, 1.0], {"subtype": "segment", "stroke": "#ccc"}], [[-5.0, 2.0], [5.0, 2.0], {"subtype": "segment", "stroke": "#ccc"}], [[-5.0, 3.0], [5.0, 3.0], {"subtype": "segment", "stroke": "#ccc"}], [[-5.0, 4.0], [5.0, 4.0], {"subtype": "segment", "stroke": "#ccc"}], [[-5.0, 5.0], [5.0, 5.0], {"subtype": "segment", "stroke": "#ccc"}], [[-5.0, 6.0], [5.0, 6.0], {"subtype": "segment", "stroke": "#ccc"}], [[-5.0, 7.0], [5.0, 7.0], {"subtype": "segment", "stroke": "#ccc"}], [[-5.0, 8.0], [5.0, 8.0], {"subtype": "segment", "stroke": "#ccc"}], [[-5.0, 9.0], [5.0, 9.0], {"subtype": "segment", "stroke": "#ccc"}], [[-5.0, -11.0], [-5.0, 9.0], {"subtype": "segment", "stroke": "#ccc"}], [[-4.0, -11.0], [-4.0, 9.0], {"subtype": "segment", "stroke": "#ccc"}], [[-3.0, -11.0], [-3.0, 9.0], {"subtype": "segment", "stroke": "#ccc"}], [[-2.0, -11.0], [-2.0, 9.0], {"subtype": "segment", "stroke": "#ccc"}], [[-1.0, -11.0], [-1.0, 9.0], {"subtype": "segment", "stroke": "#ccc"}], [[0.0, -11.0], [0.0, 9.0], {"subtype": "segment", "stroke": "#ccc"}], [[1.0, -11.0], [1.0, 9.0], {"subtype": "segment", "stroke": "#ccc"}], [[2.0, -11.0], [2.0, 9.0], {"subtype": "segment", "stroke": "#ccc"}], [[3.0, -11.0], [3.0, 9.0], {"subtype": "segment", "stroke": "#ccc"}], [[4.0, -11.0], [4.0, 9.0], {"subtype": "segment", "stroke": "#ccc"}], [[5.0, -11.0], [5.0, 9.0], {"subtype": "segment", "stroke": "#ccc"}], [[0.0, 0.0], [3.5999999999999996, 7.199999999999999], {"subtype": "segment", "arrow-end": "classic-wide-long"}], [[0.0, 0.0], [-3.5999999999999996, 1.7999999999999998], {"subtype": "segment", "arrow-end": "classic-wide-long"}], [[0.0, 0.0], [0.0, -9.0], {"subtype": "segment", "arrow-end": "classic-wide-long"}]], "circle": [[[0.0, 0.0], 0.1, {"fill": "black"}]], "label": [[[0.0, 0.0], "G", "above", {}], [[2.3366563145999493, 3.331671842700025], null], [[-2.0683281572999745, 0.36334368540005046], null], [[0.6, -4.5], null], [[1.0, -5.5], "\\overrightarrow{\\rm P}", "above", {}], [[4.8, 2.5999999999999996], "\\overrightarrow{\\rm R}", "above", {}], [[-1.2999999999999998, 0.8999999999999999], "\\overrightarrow{\\rm T}", "above", {}]]}
Données
- - Accélération de la pesanteur : \( g = 9,81\:\text{m}\mathord{\cdot}\text{s}^{-2} \)
- - Masse du solide : \( m = 275\:\text{g} \)
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.