You can calculate the thermal energy created when the ball hit the bat by using the Law of Conservation of Energy. Before the collision, the center-of-mass of the bat (mass 1kg) was moving at about 70mph (31m/s) and the ball (mass 0.15kg) was moving at about 90mph (40m/s). Now, calculate the initial kinetic energy.
After the collision, let’s estimate the speed of the bat at 50mph (22m/s) and the speed of the ball is 30mph (13m/s). Calculate the final kinetic energy. [Answer: 255J]. Now use the Law of Conservation of Energy to find the thermal energy created during this ball-bat collision. [Answer: 345J]
This thermal energy is detected by the camera as a higher temperature on the bat and ball. The camera shows higher temperatures as white.
Now you can try to estimate the thermal energy created the collision of the Colliding Steel Balls? What information do you need to find or estimate? Paper burns at about 200˚C. Do your numbers suggest that the paper’s temperature could rise that much?
About the Author
Dr. David Kagan has been at CSU Chico for over thirty years. During this time, Dr. Kagan has served in numerous roles including: Chair of the Department of Physics; founding Chair of the Department of Science Education; and Assistant Dean in the College of Natural Sciences to name a few. He is a regular contributor to The Physics Teacher having had over thirty papers published in the journal. Kagan continues his deep devotion to quality teaching by avidly engaging his students with methodologies adapted from the findings of Physics Education Research. In addition, he has remained true to his lifelong obsession with baseball by using the national pastime to enhance the teaching and learning of physics.