3. A 20.0 kg door with dimensions 1 : 85 cm, to 2 5.0 cm, and h, : 2.2 m has a closing mechanism attached 30.0 cm from the inside edge. The closing mechanism has two stages, the rst stage acts to swing it shut and the second acts to prevent slamming. The rst stage applies a constant 25 N force to the door until the door is still open by 25. The second stage immediately kicks in and applies a force necessary to slow the door to an angular speed of .25 rad/s before the door is closed. The door begins from an open angle of 110. How much work does the closing mechanism do during each stage. (The moment of inertia of a thin, uniform slab rotating about one edge is the same as that of a thin rod rotating about one edge.)