You are riding on a skateboard. If you are on a rough asphalt road and you push off as hard as you can one time, you will coast for 20 feet before you stop. If you are on a
smooth concrete sidewalk and you push off as hard as you can, you will coast for 30
feet before you stop. What force is causing you to slow down to a stop on each
surface? Why are you able to coast farther on one surface than the other?

Aproduction line at v. j. sugumaran's machine shop has three stations. the first station can process a unit in 7 minutes. the second station has two identical machines, each of which can process a unit in 16 minutes (each unit only needs to be processed on one of the two machines). the third station can process a unit in 10 minutes. ▼ is the bottleneck station, with a bottleneck time of nothing minutes per unit (enter your response as a whole number).