Wednesday Summary

Today in class we finished up on the quote and began on a class lab. To start, we measured out the force of a spring stretched out to .5m. This turned out to be 1 Newton. Using logic, and then proving it with a force measurer, we determined that 2 springs had a force of 2 Newtons. Then we measured the acceleration of the cart when the cart had the two different forces acting on it. (Three times averaged for accuracy) The average acceleration of the cart with one spring pulling was .23 m/s^2 with two springs .52 m/s^2. Then Mr. Burk set the two springs (1 N each) to pull on the cart at opposing, 22.5 degree angles. He asked us what the net force would be. Almost unanimously, the class the decided 2 N. 1+1=2 right? (The dissenters couldn't say why not) Since the 2 N force would be the same as the acceleration in the 2 spring measurement. However, when we measured the acceleration, we found it to be about .33 m/s^2, not the .52 we expected. The reason was because the net force in the direction we were measuring wasn't 2 N. We used a ratio to prove this. F(1)/F(2)=A(1)/A(2). When we set the ratio up with all our known data (F(1), A(1), and A(2)) and solved for F(2) we found that the force was equal to 1.4 N. That's right 1+1=1.4. Afterwards we learned that forces acting at angles can be added by vectors. Study hard for the Assessment tomorrow!

This may have something to do with what we did today, but I'm not sure. Regardless, it's pretty cool.

http://www.youtube.com/watch?v=s2EMXle8raw&feature=related