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