Jump start physics problem with a mass on a spring. This video explains the setup, key assumptions, and the step-by-step physics needed to solve for motion, energy, and forces in a spring–mass system.

Multi-ignition wildfires are not overly common. But when individual fires do converge, the consequences can be catastrophic.

The word “influence” is related to “flow,” at one point literally referring to the power “flowing” from the stars to shape ...