Abowler throws a bowling ball of radius r = 11 cm down the lane with initial speed v₀ = 7.5 m/s. the ball is thrown in such a way that it skids for a certain distance before it starts to roll. it is not rotating at all when it first hits the lane, its motion being pure translation. the coefficient of kinetic friction between the ball and the lane is 0.29.
(a) for what length of time does the ball skid? s
(b) how far down the lane does it skid? m
(c) how fast is it moving when it starts to roll? m/s

You have two photos of a person walking. one shows the person at the corner of third and main streets, the other shows the person at the corner of tenth and main streets. there are lampposts at every corner in this town, and the first picture shows it to be 10: 32: 00 exactly. the second picture shows it to be 10: 49: 30. you know three facts: (1) all of the clocks are synchronized; (2) there are exactly 12 equal-sized blocks per kilometer in this town; and (3) the streets that cross main in this area are numbered consecutively, with no interruptions. what is the person’s average speed in kilometers per hour?