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": [[-8.0, 8.0], [-3.0, 10.0]], "scale": [20, 20]}, "line": [[[-7.0, -2.0], [7.0, -2.0], {"subtype": "segment", "stroke": "#ccc"}], [[-7.0, -1.0], [7.0, -1.0], {"subtype": "segment", "stroke": "#ccc"}], [[-7.0, 0.0], [7.0, 0.0], {"subtype": "segment", "stroke": "#ccc"}], [[-7.0, 1.0], [7.0, 1.0], {"subtype": "segment", "stroke": "#ccc"}], [[-7.0, 2.0], [7.0, 2.0], {"subtype": "segment", "stroke": "#ccc"}], [[-7.0, 3.0], [7.0, 3.0], {"subtype": "segment", "stroke": "#ccc"}], [[-7.0, 4.0], [7.0, 4.0], {"subtype": "segment", "stroke": "#ccc"}], [[-7.0, 5.0], [7.0, 5.0], {"subtype": "segment", "stroke": "#ccc"}], [[-7.0, 6.0], [7.0, 6.0], {"subtype": "segment", "stroke": "#ccc"}], [[-7.0, 7.0], [7.0, 7.0], {"subtype": "segment", "stroke": "#ccc"}], [[-7.0, 8.0], [7.0, 8.0], {"subtype": "segment", "stroke": "#ccc"}], [[-7.0, 9.0], [7.0, 9.0], {"subtype": "segment", "stroke": "#ccc"}], [[-7.0, -2.0], [-7.0, 9.0], {"subtype": "segment", "stroke": "#ccc"}], [[-6.0, -2.0], [-6.0, 9.0], {"subtype": "segment", "stroke": "#ccc"}], [[-5.0, -2.0], [-5.0, 9.0], {"subtype": "segment", "stroke": "#ccc"}], [[-4.0, -2.0], [-4.0, 9.0], {"subtype": "segment", "stroke": "#ccc"}], [[-3.0, -2.0], [-3.0, 9.0], {"subtype": "segment", "stroke": "#ccc"}], [[-2.0, -2.0], [-2.0, 9.0], {"subtype": "segment", "stroke": "#ccc"}], [[-1.0, -2.0], [-1.0, 9.0], {"subtype": "segment", "stroke": "#ccc"}], [[0.0, -2.0], [0.0, 9.0], {"subtype": "segment", "stroke": "#ccc"}], [[1.0, -2.0], [1.0, 9.0], {"subtype": "segment", "stroke": "#ccc"}], [[2.0, -2.0], [2.0, 9.0], {"subtype": "segment", "stroke": "#ccc"}], [[3.0, -2.0], [3.0, 9.0], {"subtype": "segment", "stroke": "#ccc"}], [[4.0, -2.0], [4.0, 9.0], {"subtype": "segment", "stroke": "#ccc"}], [[5.0, -2.0], [5.0, 9.0], {"subtype": "segment", "stroke": "#ccc"}], [[6.0, -2.0], [6.0, 9.0], {"subtype": "segment", "stroke": "#ccc"}], [[7.0, -2.0], [7.0, 9.0], {"subtype": "segment", "stroke": "#ccc"}], [[-1.2862393885688164, 3.77174363314129], [-0.5144957554275263, 5.057983021710106], {"subtype": "segment"}], [[-0.5144957554275263, 5.057983021710106], [2.0579830217101063, 3.5144957554275265], {"subtype": "segment"}], [[2.0579830217101063, 3.5144957554275265], [1.2862393885688164, 2.2282563668587105], {"subtype": "segment"}], [[-5.0, 6.874642784226795], [-0.9003675719981714, 4.414863327425698], {"subtype": "segment"}], [[-5.0, 6.0], [-5.0, 8.0], {"subtype": "segment"}], [[5.0, 0.0], [-5.0, 6.0], {"subtype": "segment"}], [[-5.0, 0.0], [5.0, 0.0], {"subtype": "segment"}]], "arc": [[[5.0, 0.0], [1.5, 1.5], 149.03624346792648, 180.0, false, {}]], "circle": [[[0.38587181657064495, 3.643119694284408], 0.1, {"fill": "black"}]], "label": [[[3.0, -0.5], "\\alpha", "above", {}], [[-0.11412818342935505, 3.143119694284408], "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], [-9.0, 7.0]], "scale": [40, 40]}, "line": [[[-4.0, -8.0], [4.0, -8.0], {"subtype": "segment", "stroke": "#ccc"}], [[-4.0, -7.0], [4.0, -7.0], {"subtype": "segment", "stroke": "#ccc"}], [[-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, 5.0], [4.0, 5.0], {"subtype": "segment", "stroke": "#ccc"}], [[-4.0, 6.0], [4.0, 6.0], {"subtype": "segment", "stroke": "#ccc"}], [[-4.0, -8.0], [-4.0, 6.0], {"subtype": "segment", "stroke": "#ccc"}], [[-3.0, -8.0], [-3.0, 6.0], {"subtype": "segment", "stroke": "#ccc"}], [[-2.0, -8.0], [-2.0, 6.0], {"subtype": "segment", "stroke": "#ccc"}], [[-1.0, -8.0], [-1.0, 6.0], {"subtype": "segment", "stroke": "#ccc"}], [[0.0, -8.0], [0.0, 6.0], {"subtype": "segment", "stroke": "#ccc"}], [[1.0, -8.0], [1.0, 6.0], {"subtype": "segment", "stroke": "#ccc"}], [[2.0, -8.0], [2.0, 6.0], {"subtype": "segment", "stroke": "#ccc"}], [[3.0, -8.0], [3.0, 6.0], {"subtype": "segment", "stroke": "#ccc"}], [[4.0, -8.0], [4.0, 6.0], {"subtype": "segment", "stroke": "#ccc"}], [[0.0, 0.0], [2.647058823529412, 4.411764705882353], {"subtype": "segment", "arrow-end": "classic-wide-long"}], [[0.0, 0.0], [-2.647058823529412, 1.5882352941176474], {"subtype": "segment", "arrow-end": "classic-wide-long"}], [[0.0, 0.0], [0.0, -6.0], {"subtype": "segment", "arrow-end": "classic-wide-long"}]], "circle": [[[0.0, 0.0], 0.1, {"fill": "black"}]], "label": [[[0.0, 0.0], "G", "above", {}], [[1.8380251671922325, 1.8971848996846608], null], [[-1.632226865021222, 0.27962189163129725], null], [[0.6, -3.0], null], [[1.0, -4.0], "\\overrightarrow{\\rm P}", "above", {}], [[4.3235294117647065, 1.2058823529411766], "\\overrightarrow{\\rm R}", "above", {}], [[-0.8235294117647061, 0.7941176470588237], "\\overrightarrow{\\rm T}", "above", {}]]}
Données
- - Accélération de la pesanteur : \( g = 9,81\:\text{m}\mathord{\cdot}\text{s}^{-2} \)
- - Masse du solide : \( m = 550\:\text{g} \)
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.