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, 12.0]], "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, 11.0], [9.0, 11.0], {"subtype": "segment", "stroke": "#ccc"}], [[-9.0, -2.0], [-9.0, 11.0], {"subtype": "segment", "stroke": "#ccc"}], [[-8.0, -2.0], [-8.0, 11.0], {"subtype": "segment", "stroke": "#ccc"}], [[-7.0, -2.0], [-7.0, 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"}], [[7.0, -2.0], [7.0, 11.0], {"subtype": "segment", "stroke": "#ccc"}], [[8.0, -2.0], [8.0, 11.0], {"subtype": "segment", "stroke": "#ccc"}], [[9.0, -2.0], [9.0, 11.0], {"subtype": "segment", "stroke": "#ccc"}], [[-1.3023647131866887, 4.744208407535251], [-0.5581563056514378, 6.0465731207219395], {"subtype": "segment"}], [[-0.5581563056514378, 6.0465731207219395], [2.0465731207219395, 4.558156305651438], {"subtype": "segment"}], [[2.0465731207219395, 4.558156305651438], [1.3023647131866891, 3.2557915924647496], {"subtype": "segment"}], [[-7.0, 8.863813330174844], [-0.9302605094190632, 5.395390764128596], {"subtype": "segment"}], [[-7.0, 8.0], [-7.0, 10.0], {"subtype": "segment"}], [[7.0, 0.0], [-7.0, 8.0], {"subtype": "segment"}], [[-7.0, 0.0], [7.0, 0.0], {"subtype": "segment"}]], "arc": [[[7.0, 0.0], [1.5, 1.5], 150.25511870305778, 180.0, false, {}]], "circle": [[[0.3721042037676253, 4.651182356593345], 0.1, {"fill": "black"}]], "label": [[[5.0, -0.5], "\\alpha", "above", {}], [[-0.12789579623237468, 4.151182356593345], "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], [-11.0, 9.0]], "scale": [40, 40]}, "line": [[[-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, -10.0], [-5.0, 8.0], {"subtype": "segment", "stroke": "#ccc"}], [[-4.0, -10.0], [-4.0, 8.0], {"subtype": "segment", "stroke": "#ccc"}], [[-3.0, -10.0], [-3.0, 8.0], {"subtype": "segment", "stroke": "#ccc"}], [[-2.0, -10.0], [-2.0, 8.0], {"subtype": "segment", "stroke": "#ccc"}], [[-1.0, -10.0], [-1.0, 8.0], {"subtype": "segment", "stroke": "#ccc"}], [[0.0, -10.0], [0.0, 8.0], {"subtype": "segment", "stroke": "#ccc"}], [[1.0, -10.0], [1.0, 8.0], {"subtype": "segment", "stroke": "#ccc"}], [[2.0, -10.0], [2.0, 8.0], {"subtype": "segment", "stroke": "#ccc"}], [[3.0, -10.0], [3.0, 8.0], {"subtype": "segment", "stroke": "#ccc"}], [[4.0, -10.0], [4.0, 8.0], {"subtype": "segment", "stroke": "#ccc"}], [[5.0, -10.0], [5.0, 8.0], {"subtype": "segment", "stroke": "#ccc"}], [[0.0, 0.0], [3.4461538461538455, 6.030769230769231], {"subtype": "segment", "arrow-end": "classic-wide-long"}], [[0.0, 0.0], [-3.4461538461538455, 1.9692307692307687], {"subtype": "segment", "arrow-end": "classic-wide-long"}], [[0.0, 0.0], [0.0, -8.0], {"subtype": "segment", "arrow-end": "classic-wide-long"}]], "circle": [[[0.0, 0.0], 0.1, {"fill": "black"}]], "label": [[[0.0, 0.0], "G", "above", {}], [[2.2440228083515983, 2.717701252370515], null], [[-2.020760286091023, 0.4636694993407088], null], [[0.6, -4.0], null], [[1.0, -5.0], "\\overrightarrow{\\rm P}", "above", {}], [[4.723076923076922, 2.0153846153846153], "\\overrightarrow{\\rm R}", "above", {}], [[-1.2230769230769227, 0.9846153846153843], "\\overrightarrow{\\rm T}", "above", {}]]}
Données
- - Accélération de la pesanteur : \( g = 9,81\:\text{m}\mathord{\cdot}\text{s}^{-2} \)
- - Masse du solide : \( m = 245\:\text{g} \)
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.