Realistic answers and the state of physics resources on the internet
Today, I was being a bit lazy when making up a quiz, and I decided to google “momentum problems.” Big mistake. Check out the top hit.
It’s a randomized page of simple problems, so you won’t get the same results I did, but Here’s a sample:
A small car (mass = 133 kilograms), moving at 98 m/s, crashes head on with a 532 kilogram truck moving at -63 m/s in the opposite direction. If the two cars become ?intertwined and mangled (inelastic), with what velocity does the wreckage move? (Don’t forget direction!)
Are you serious? What small car has a mass of 113kg and can move at 98 m/s (219 mi/hr)?
This gets me thinking two thoughts:
- How are we teaching students to check their answers for reasonability? Is this part of getting them to see the significance of their work? I love open ended problems, but I think I need to work more on getting my students to think about the significance of their findings, and question the reasonability of their results.
- Why are most of the resources that google returns for physics teaching searches so bad? It took me years of searching physics teaching blogs and finding a bunch of useless stuff before I ever stumbled upon Frank Noschese’s blog. Why is this? Are people linking to crappy problems that involve clown cars traveling at Ferrari speeds? Why would this be? And more importantly, what can be done about it?