Today, I demonstrated an extreme example of an unbalanced force acting on an object with our ping pong ball cannon. My colleague created a great problem which my students will solve tomorrow:
We can estimate the speed of the ping pong ball from yesterday’s demo with the help of some background information, some guesstimates, some assumptions, and a little physics. The ball has a mass of 2.7g, assuming a full vacuum of 101,325 Pascals, and cross-sectional area of the ball of 1.26×10-3 m2. The result is approximately 127.6 N of force pushing the ball inside the 10-ft long tube. Draw a free body diagram of the ball in the tube, and estimate its acceleration. Then sketch the beginning and ending conditions of the ball, including all variables and find its exit speed in mph (pay close attention to ALL units). o you think the ping pong ball was actually going this fast? Why or why not?
Here’s what it did to my soda can.