At Camp Ketcha in Scarborough on Friday, 10 students from Portland High School and their physics teacher, Rosalee Lamm, tested out a zip line that the students designed as part of their physics classes this semester.

“There were a lot of physics considerations in the design process,” Lamm said. Students had to think about the amount of tension the line needed, how much sag it should have and how to regulate the speed of people using the zip line.

On Friday, at the base of a tall pine where the zip line begins, students calculated the amount of energy a student would start with while sitting on the launch platform, which is 30 feet off the ground, and what the maximum potential speed would be along the 280-foot zip line.

The students raised about $600 of the $3,000 needed to fund the project. The remainder was donated by L.L. Bean.