Achieving velocity effectively. (19th July 2018)

• Record Type: Journal Article
• Authors: Kaufman, Richard
• Is Part Of: Physics education. Volume 53:Number 5(2018:Sep.)
• Publication Date: 2018-07-19
• Subjects: Physics -- Study and teaching (Secondary) -- Periodicals; 530.0712
• DOI: 10.1088/1361-6552/aad057
• Languages: English
• ISSNs: 0031-9120

Abstract

Abstract: Of course, it is more effective to throw a baseball to achieve a specified final velocity while firmly standing on Earth than while standing on a level skateboard, which moves in the opposite direction of the baseball. But does this mean that it is always best to accelerate an object while anchored to an 'infinitely' massive object, like the Earth? No. This note shows that a method using springs and expelled masses can use the same amount of energy. The same amount of work is used as long as processes (involving masses, springs, etc…) end up with the expelled masses at rest relative to Earth and the payload at the final velocity.