(25%) Problem 1: Two children push on opposite sides of a door during play. Both push horizontally and perpendicular to the surface of the door. One Child pushes with a force of 19.5 N at a distance of 0.62 m from the hinges, and the second child pushes at a distance of 0.4 '5 m. |:| @ What is the magnitude of the force, in newtons, the second child must exert to keep the door from moving? Assume friction is negligible. F2=| , Select the examples below that have a net torque of zero about the axis perpendicular to the page and extending from the center of the puck. E] F C] F C] F (25%) Problem 2: A circular air hockey puck of radius 1' slides across a frictionless air hockey table and is subjected to several forces as shown below. The magnitude and direction of each force is given. Forces are applied at either the center of mass of the puck, the outer edge (a distance r from the center), or a distance halfwaf frat between the center and the outer edge. building. (25%) Problem 3: A painter (of mass '9 kg) needs to reach out from a scaffolding to paint the side of a building, so he lays a plank across two bars of the scaffolding, and puts a heavy bucket of mass 25 kg directly over one of the bars (see gure). You can assume the plank is massless, and is long enough to reach to the other I ,r L ' d ' A If the bars are separated by a distance 1.4 111, how far, (i, from the bar on the the right can the painter walk before the plank starts to fall? d: l m 1% Problem 4: Two children of mass 19 kg and 34 kg sit balanced on a seesaw with the pivot point located at the center of the seesaw. & If the children are separated by a distance of 3.0 m, at what distance, in meters, from the pivot point is the smaller child sitting in order to maintain the balance? ' g