Module Four Summary and begin Popsicle stick catapult lab

Wrapped up module four with test of problems concerning the addition of vectors.

The main take-away from vector addition:
If they ask to add two vectors, you have to get the x and y components of each vector and add together.  Then use the Pythagorean theorem to solve for the magnitude.  Then use the inverse tangent to get the angle.   If they give you one vector and ask for the x and y components you take the sine and cosine of the angle times the magnitude.


We made catapults.  Our plan is to use these math calculations next week to analyze parabolic
motion.

Today we used out catapults to shoot marshmallows.  We measured the height and length of the motion.  We measured the time elapsed from launch to landing.  We measured the angle of the launch with a protractor.  I challenged the students to calculate the exit speed of the marshmallow.  Several had the idea to use x = Vinitial x time plus 1/2 at^2.  There are several other calculations required before this equation can be used.  They will have to follow the Dr. Math equations referred to in the previous paragraph.

Several students had difficulty getting consistent trajectories or had launches that went straight up.  We had to experiment with placement of the fulcrum, attachment points of the lever, and the attachment of the spoon to the stick.  Do not bend the spoon; that interferes with the measurement of the lever and the launch angle.  When we were making the catapults I said to use only rubber bands and not tape.  Those who used tape had difficulty making the adjustments needed to fix the trajectory of their launch.