Mechanical energy swing because of the work done by the pendulum to oppose these non-conservative forces. That the loss of mechanical energy in a system always resulted in an increase of the system's temperature has been known for a long time, but it was the amateur physicist James Prescott Joule who first experimentally demonstrated how a certain amount of work done against friction resulted in a definite quantity of heat which should be conceived as the random motions of the particles that comprise matter. This equivalence between mechanical energy and heat is especially important when considering colliding objects. In an elastic collision,
Dandong–Dalian intercity railway and a half years and was started on 17 March 2010. It started operation on 17 December 2015. Dandong–Dalian intercity railway The Dandong–Dalian intercity railway () is a high-speed line operated by China Railway High-speed within the Liaodong Peninsula of Liaoning province, connecting the coastal cities of Dandong and Dalian. Dandong–Dalian intercity railway is broken down into three segments: Dandong–Zhuanghe, Zhuanghe–Dengshahe, and Dengshahe–Dalian. It will have a total length of about , of which will be in the Dandong prefectural area, will be in the Dalian region. The total investment is estimated to be about 14.7 billion yuan with a