(1) A block is placed on a wooden plank, which is initiallyhorizontal. One end of the plank is slowly raised to make it moreand more inclined, and for a while the block stays in place on theplank and doesn't slide due to static friction. Finally, when theplank reaches an incline of 56.3o above horizontal, theblock begins to slide. What isthe  coefficient of staticfriction between the block and the plank?
(2) Continuing the story... after the block begins sliding downthe incline at 56.3o, you measure its acceleration downthe plank as 7.42 m/s2. What is thecoefficient of kinetic friction betweenthe block and the plank?
These will be clicker questions on Wednesday, and we will worktogether through some problems involving tension and pairs ofobjects.
