Foo... Routing xTool 40W Upgrade... age Oregon Sports Wat... 10 8cm Genuine BE... Kelio Figure 2 shows a decorator's plank, which is 5 m in length, uniform, and supported on two trestles. The mass of the plank is 48 kg and the mass of the decorator is 68 kg. In order to paint a stairwell, the decorator has to position themselves at point A, as shown on Figure 2. To stop the plank tipping, the decorator's assistant pulls down a rope attached at point B. C 1.5 m 2 m 1 m Figure 2 The decorator's plank (not drawn to scale) Show description The Open University a. Draw a free body diagram showing all the forces acting on the plank and the distances from point C (the left-hand support) at which each force acts. (4 marks) b. State, in words, two conditions that must be satisfied for the plank to be stationary and stable. (2 marks) c. For each of the two conditions you have identified in Part (b), using the information contained in your diagram, write an equation that must be satisfied for the plank to remain stationary. Do not include units in your equations. (4 marks) Q Search LOD myhp W : d. What is the minimum force that the assistant must apply to the rope to prevent the plank from tipping? (Hint, think about the reaction forces at the trestle nearest the rope.) Give your answers to 2 significant figures. (6 marks) e. The assistant gets tired and instead of pulling the rope attaches a mass of 27 kg to it. Calculate the stress in the rope knowing that its diameter is 24 mm. Give your answer to 2 significant figures. (4 marks) Take the acceleration due to gravity, g, to be 9.8 m s. < Previous Question 3 Next > Question 5 View page tour Saved for later Send feedback Pr do Q Search LOD mwhp W