Please help with 3 and 4

3. Starting from rest, a 0.75 kg brick is placed onto the rim ofa 4-kg uniform circular disk with a 3.0-m radius rotating at a rate of 25 revolutions per minute counterclockwise as shown below. Assuming the brick is a point mass, determine; a. The initial angular momentum of the disk. ' b. The brick's moment of inertiaafter it attaches to the disk. b. The nal angular velocity of the system after the brick attaches to [the rim. c. The brick's nal angular momentum. 4. An 80-kg superhero sits at rest on top of a 5.0meter wall as shown below. Using a rope, he swings toward a 70-kg villain who is initially at rest. The superhero releases the rope just before colliding with and clinging to the villain. After the collision, the superhero and villain slide together across the oor until they are brought to rest by friction. Determine; The superhero's velocity when he descends to a height of 3.0 m above the ground. . The superhero's velocity just before he collides with the villain. The momentum of the superhero/villain system immediately following the collision. . The impulse delivered by the oor to the combined masses. If the men slide across the oor over a distance of 4.75 m, apply the WorkEnergy Theorem to determine the force of friction acting upon them. sinners*9 My >l Ax = 4.75 in