1. Ian leaves his 3rd floor apartment to pick up lunch, but when he gets outside, he realizes that he has forgotten his car keys. His wife, Jane, realizes this and opens the window to toss his keys to him. Jane tosses the keys, which have a mass of 35 grams, with an initial speed of 3.0 m/s. By the time the keys reach Ian, gravity has done +3.5 J of work to the keys, and air resistance has done -2.1 J of work to the keys. What is the speed of the car keys when they reach Ian, just before he catches them? 2. 5. After a bicyclist travels 20 km, how many rotations have the wheels made? The radius of the bicycle wheels is 0.30 m.
3. 6. A 35 kg child slides down a 5.0 m long slide as shown. As the child slides, there is a kinetic friction force between the child and the slide with a coefficient of kinetic friction of 0.20. How much work (including the sign) did the gravitational force do to the child when the child slides from the top of the slide to the bottom?