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": [[-6.0, 6.0], [-3.0, 8.0]], "scale": [20, 20]}, "line": [[[-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, -2.0], [-5.0, 7.0], {"subtype": "segment", "stroke": "#ccc"}], [[-4.0, -2.0], [-4.0, 7.0], {"subtype": "segment", "stroke": "#ccc"}], [[-3.0, -2.0], [-3.0, 7.0], {"subtype": "segment", "stroke": "#ccc"}], [[-2.0, -2.0], [-2.0, 7.0], {"subtype": "segment", "stroke": "#ccc"}], [[-1.0, -2.0], [-1.0, 7.0], {"subtype": "segment", "stroke": "#ccc"}], [[0.0, -2.0], [0.0, 7.0], {"subtype": "segment", "stroke": "#ccc"}], [[1.0, -2.0], [1.0, 7.0], {"subtype": "segment", "stroke": "#ccc"}], [[2.0, -2.0], [2.0, 7.0], {"subtype": "segment", "stroke": "#ccc"}], [[3.0, -2.0], [3.0, 7.0], {"subtype": "segment", "stroke": "#ccc"}], [[4.0, -2.0], [4.0, 7.0], {"subtype": "segment", "stroke": "#ccc"}], [[5.0, -2.0], [5.0, 7.0], {"subtype": "segment", "stroke": "#ccc"}], [[-1.2480754415067656, 2.8320502943378436], [-0.4160251471689219, 4.080125735844609], {"subtype": "segment"}], [[-0.4160251471689219, 4.080125735844609], [2.080125735844609, 2.416025147168922], {"subtype": "segment"}], [[2.080125735844609, 2.416025147168922], [1.2480754415067659, 1.1679497056621564], {"subtype": "segment"}], [[-3.0, 4.901387818865997], [-0.8320502943378438, 3.4560880150912263], {"subtype": "segment"}], [[-3.0, 4.0], [-3.0, 6.0], {"subtype": "segment"}], [[3.0, 0.0], [-3.0, 4.0], {"subtype": "segment"}], [[-3.0, 0.0], [3.0, 0.0], {"subtype": "segment"}]], "arc": [[[3.0, 0.0], [1.5, 1.5], 146.30993247402023, 180.0, false, {}]], "circle": [[[0.4160251471689218, 2.6240377207533827], 0.1, {"fill": "black"}]], "label": [[[1.0, -0.5], "\\alpha", "above", {}], [[-0.0839748528310782, 2.1240377207533827], "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": [[-7.0, 7.0], [-12.0, 9.0]], "scale": [40, 40]}, "line": [[[-6.0, -11.0], [6.0, -11.0], {"subtype": "segment", "stroke": "#ccc"}], [[-6.0, -10.0], [6.0, -10.0], {"subtype": "segment", "stroke": "#ccc"}], [[-6.0, -9.0], [6.0, -9.0], {"subtype": "segment", "stroke": "#ccc"}], [[-6.0, -8.0], [6.0, -8.0], {"subtype": "segment", "stroke": "#ccc"}], [[-6.0, -7.0], [6.0, -7.0], {"subtype": "segment", "stroke": "#ccc"}], [[-6.0, -6.0], [6.0, -6.0], {"subtype": "segment", "stroke": "#ccc"}], [[-6.0, -5.0], [6.0, -5.0], {"subtype": "segment", "stroke": "#ccc"}], [[-6.0, -4.0], [6.0, -4.0], {"subtype": "segment", "stroke": "#ccc"}], [[-6.0, -3.0], [6.0, -3.0], {"subtype": "segment", "stroke": "#ccc"}], [[-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, -11.0], [-6.0, 8.0], {"subtype": "segment", "stroke": "#ccc"}], [[-5.0, -11.0], [-5.0, 8.0], {"subtype": "segment", "stroke": "#ccc"}], [[-4.0, -11.0], [-4.0, 8.0], {"subtype": "segment", "stroke": "#ccc"}], [[-3.0, -11.0], [-3.0, 8.0], {"subtype": "segment", "stroke": "#ccc"}], [[-2.0, -11.0], [-2.0, 8.0], {"subtype": "segment", "stroke": "#ccc"}], [[-1.0, -11.0], [-1.0, 8.0], {"subtype": "segment", "stroke": "#ccc"}], [[0.0, -11.0], [0.0, 8.0], {"subtype": "segment", "stroke": "#ccc"}], [[1.0, -11.0], [1.0, 8.0], {"subtype": "segment", "stroke": "#ccc"}], [[2.0, -11.0], [2.0, 8.0], {"subtype": "segment", "stroke": "#ccc"}], [[3.0, -11.0], [3.0, 8.0], {"subtype": "segment", "stroke": "#ccc"}], [[4.0, -11.0], [4.0, 8.0], {"subtype": "segment", "stroke": "#ccc"}], [[5.0, -11.0], [5.0, 8.0], {"subtype": "segment", "stroke": "#ccc"}], [[6.0, -11.0], [6.0, 8.0], {"subtype": "segment", "stroke": "#ccc"}], [[0.0, 0.0], [4.153846153846153, 6.230769230769232], {"subtype": "segment", "arrow-end": "classic-wide-long"}], [[0.0, 0.0], [-4.153846153846153, 2.7692307692307683], {"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", {}], [[2.5761532535257827, 2.7825644976494783], null], [[-2.409743194658214, 0.8853852080126778], null], [[0.6, -4.5], null], [[1.0, -5.5], "\\overrightarrow{\\rm P}", "above", {}], [[5.076923076923077, 2.115384615384616], "\\overrightarrow{\\rm R}", "above", {}], [[-1.5769230769230766, 1.3846153846153841], "\\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.