Design and evaluate a device that protects a fragile object during an impact, applying the idea that spreading a collision over more time reduces peak force.
When something stops suddenly, its momentum has to change to zero, which requires a force acting over some time. The same change can happen with a huge force over a very short time (a hard crash) or a smaller force over a longer time (a gentle stop) -- the momentum change is identical, but the felt force is very different.
Car crumple zones, bicycle helmets, and padded packaging all stretch the stopping time, lowering the peak force. A rigid, non-crushing design forces the same stop to happen almost instantly, meaning a much larger peak force -- often exactly what causes damage.
Mastery looks like: They explain, using stopping time and distance, why padding or crumple zones reduce impact force, and apply that to evaluate a design.
Common stumbles: Believing a stiffer, more rigid design is automatically safer; focusing on material strength instead of how much the design extends stopping time.