Kelly Liang9/12/20142Hoop/Spit Ball LabIntroduction: Objects launched from a certain angle experience projectile motion, in which these objects velocity is determined by horizontal and vertical components in a situation where gravity exists. In the frame of reference, upward direction is positive. To make our calculations easier, air resistance is omitted.

Purpose:To get spitball through hoop set at a given height by predicting the angle it should be launched.

Question:At what angle should the spitball be launched in order to travel through the hoop?

Hypothesis:If the spitball is launched at a degree which fits with our calculation, then the spitball will travel through the hoop that is set at a given height.

Materials: Some paper towel1 strawMeter sticks1 protractor

Procedure: 1. Make some spitball out of paper towel. 2. Measure the horizontal and vertical distances between the hoop and the position at which the spitball will be launched. 3. Calculate the angle at which the spitball should be launched using the given data. 4. Launch the spitball at the angle calculated.

Data/Calculations: Horizontal distance (x)=3.5mVertical distance (y)=0.40m

Conclusion:When we tested our hypothesized angle, we had four trials, Although the spitball did not travel through the hoop as we expected, in two of the trials the spitball just travel really closely to the hoop. The most probable experimental error was the shaking of my team members hand when she held the straw and was ready to launch the spitball. Another error was also the shaking of my hand, for I was supposed to hold the protractor and measure the angle. These errors resulted in the shift of the actual angle from our ideal or theoretical angle, which was crucial to our success in launching the spitball through the hoop.