This is horrible. First off, I earlier explained that friction (at least from the ground) is not in play here. You are diving to touch the bag immediately, not to slide into it. Second...the bold part. A science teacher's head might explode if a student told him this with no explanation. No, you just explained why when you stop running you don't necessarily decelerate. F=ma. There is air-resistance...but that effects you when you are running, too. In fact, continuing to run will INCREASE the frictional forces working against you as you are still connecting with the ground. I'll conceed the point that not taking those last two steps will decrease your speed as you cross the bag. I am not arguing that and never will. But the advantage of being able to reach out and touch the bag as your center of mass is significantly behind the bag offsets that slight loss of speed. If you imagine Wilt Chamberlain diving toward the bag instead of running over it, can you imagine the advantage of having your center of mass behind the bag and still being there? The only difference there is scale. [bragging]Claiming that science says it's impossible with a Geophysicist probably isn't your best bet, btw. [/bragging] Friction is not at play? You are either joking or you've never seen someone slide into first base in a cloud of dust. The center of mass has nothing to do with sliding or running, velocity does. Sliding cannot be faster than running through a base for the following reasons: 1. a person has to stop running to slide thereby slowing down 2. when a person slides more surface area is in contact with the ground thereby slowing down The only reason that people slide into second base, third, and home is: 1. To avoid a tag. 2. so they don't lose contact with the base when tagged. We can have a debate about lunging vs sliding if you want, but there is no debate about running vs sliding. Q: Why don't sprinters or speed skaters slide to the finish line? A: Because sliding slows them down. This is pretty ridiculous. 1)I'm not sliding before I reach the bag, just after. After I've already touched it. Yes, you could easily get hurt "DIVING" at the bag. Thats not the point. 2)I understand the reasons for sliding into 2nd/3rd etc. That's a different situation. 3)The sprinters thing has already been covered. If to win a race you only had to cross the finish line with the tip of your finger, sprinters would be diving for the line with their hands stretched out in front of them. Since that doesn't win a race, they don't. One more time, to get to the bag fastest, with any part of your body, you should probably dive head first, arms outstretched at the bag. You should time it so that the first thing your body (hand) comes in contact with (other than air) is the bag. No one will do this since you will get hurt. What a dumb argument.