86. A material point varies according to the equation x = Acosωt, where A = 5 cm and ω = π / 12 c-1. When the restoring force F for the first time reaches -12 mN, the potential energy of a point P is equal to 0.15 mJ. Determine: 1) the time t; 2) corresponding to the time phase ωt.

Detailed solution. Decorated in Microsoft Word 2003. (Target decided to use formula editor)