The University Physics Competition 

The 2018 University Physics Competition

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?

Teams were given 48 hours to submit solution papers to these problems.  Results of the contest will be posted here before January 31, 2019.