Bert Freudenberg wrote:
If we use a protractor to tilt the inclined plane (say) every 5? then we can write down the different forces down the plane. If we divide these numbers by the maximum weight when the angle is 90, we will get numbers between 0 and 1. These numbers can be put into a holder as a table of values and used in a wide variety of projects, including making a roller coaster. So there is no need to use the idea of "sine" -- and this makes projects that need these ratios -- like roller coasters -- much more in the range of 5-7th graders.
What do you think of measuring the forces in the Etoy itself (for example, by taking the vertical extent of a rotated line)? Of course, I can see the value of using real-world data. Do you think it's too large a step to "see" the height of the angle, which is proportional to the force?
I think it would be nice to have a playground that had gravity "turned on", so all the stuff put in it would act acording.
Then you could "view" object and it would tell you the forces.
Karl