All the problems on this page refer to the following situation. A trebuchet ( diagram at right ) is a siege weapon used in the Middle Ages to lob boulders at the enemy. A boulder is lobbed and strikes the castle 3.0( s ) later. It strikes the castle at the boulder's top of trajectory ( diagram at right ) . In the space below and grid at right sketch the interaction and force diagrams at the instant of impact into the vertical castle wall. In the grid, sketch and label all forces at the instant when the force of the wall on the boulder is twice the weight of the boulder. Include F in another color consistent with tip to tail vector addition