A billboard, mass 15 kg, is suspended from a roof by means of a light inextensible string. Force F pulls the billboard sideways, as shown in the diagram below.
When the angle between the roof and the string is 40°, a closed vector diagram is obtained for all the forces acting on the billboard.
2.1 What deduction can be made when the forces acting on an object forms a closed vector diagram? (2)
2.2 Calculate the weight of the billboard. (2)
2.3 Draw a labelled closed vector diagram of ALL the forces acting on the billboard. Indicate the value of ONE of the angles. (4)
2.4 Calculate the tension in the string. (2)
2.5 The magnitude of force F is equal to the magnitude of the horizontal component of the tension in the string.
Give a reason why these two forces are NOT considered to be an action-reaction pair according to Newton’s Third Law. (1)
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