Game: route each scenario through the method that exposes the fewest hidden assumptions.

Choose the best starting method for the highlighted problem.

Stage 1: a sled starts with a known speed and stops after a known rough-track distance. Which lens is most natural first?
Stage 2: a collision lasts a few milliseconds and the force history is messy, but before-and-after speeds are known. Which lens is most natural first?
Stage 3: a box hangs from a rope and accelerates upward with known mass and acceleration. Which lens is most natural first?
Stage 4: a particle is stated to move with constant acceleration, and you know its initial speed and elapsed time. Which lens is most natural first?

Classical mechanics