The ninth annual University Physics Competition began on Friday, November 9, 2018, at 6pm MST, when the following problems were posted:

Problem A: Sending a Light Sail Propelled Nanocraft to Alpha Centauri

It has been proposed that an ultralight spacecraft, with a mass of only a few grams, could be accelerated up to approximately 20% of the speed of light by pressure on a light sail from a ground-based array of lasers.  This would require a light sail area of approximately 10 square meters and a laser array operating at a power at a level of approximately 50 gigawatts for 10 – 20 minutes.  Analyze the spacecraft’s dynamics during acceleration:  If the goal is to flyby Proxima Centauri b at closer than the Earth-Moon distance, what would be the necessary accuracy and precision of the beam from the laser array?  What would be the margin of error in the fabrication of the light sail and the uniformity of the laser beam?

Problem B: Compost Pile Sizes

Composting is the process in which microbes turn organic matter into a useful soil conditioner.  Efficient composting requires the right range of temperatures (40 – 60 degrees C), sufficient moisture content (usually 50-60%), and aeration to deliver adequate oxygen to the microbes.  Larger piles can better maintain high internal temperatures because the heat will diffuse out more slowly.  However, larger piles are also more likely to compact the material, thus inhibiting the flow of oxygen.  What pile size will result in the most efficient composting if we are working with kitchen vegetable waste in a climate where the ambient temperature ranges between 5 and 20 degrees C in a 24-hour period?   How would the most effective pile size vary depending on the ambient temperatures and the input organic materials?

The following announcement of results was made on Monday, January 21, 2019:

Full results announcement and complete listing of all medals in the 2018 University Physics Competition

We are very pleased to announce the results of the ninth annual University Physics Competition. The University Physics Competition is an international contest for undergraduate students, who worked in teams of up to three students at their home colleges and universities all over the world, and spent 48 hours during the weekend of November 9, 10, & 11, 2018, analyzing an applied scenario using the principles of physics, and writing a formal paper describing their work.

In this year’s competition 281 teams submitted papers for judging. 185 teams selected “Problem A – Sending a Light Sail Propelled Nanocraft to Alpha Centauri” and 96 teams selected “Problem B – Compost Pile Sizes.”

For Problem A, the Gold Medal Winning Teams were:

Team 158: Shubham Jain, Surabhi Gupta, & Kaavya Sahay

Institution: Indian Institute of Technology Delhi

Faculty Sponsor: Pradipta Ghosh

Team 158's 2018 Problem A Gold Medal Winning Paper

Team 258: Carles Falcó, Lucía Vílchez, & Jacob Erlikhman

Institution: University of California, Santa Barbara

Faculty Sponsor: Nathaniel Craig

Team 258's 2018 Problem A Gold Medal Winning Paper

Team 295: Li Zeyue, Liu Mingjiang, & Wu Tianhao

Institution: National University of Defense Technology

Faculty Sponsor: Yi Wenjun

For problem B, the Gold Medal Winning Teams were:

Team 240: Jaume Cunill Subiranas, Marc Serra Peralta, & Laia Waffelaert Pascual

Institution: Universitat Autònoma de Barcelona

Faculty Sponsor: Àlvar Sánchez Moreno

Team 285: Yang Mingyue, Liu Hao, & Sun Meichen

Institution: National University of Defense Technology

Faculty Sponsor: Zhong Ming

Of the 281 papers submitted in the 2018 University Physics Competition, 5 teams (1.8%) were ranked as Gold Medal Winners, 50 teams (18%) were ranked as Silver Medal Winners, 75 teams (27%) were ranked as Bronze Medal Winners, and 151 teams (54%) were ranked as Accomplished Competitors.

We extend our sincerest congratulations to each of the competing teams for their excellent work and their enthusiasm for physics!

Kelly S. Cline

Carroll College; Helena, MT

Director of the University Physics Competition

director@uphysicsc.com

www.uphysicsc.com