Multiple choice general knowledge

When glass breaks, the cracks move up to how many mph?

  1. 500

  2. 1000

  3. 2000

  4. 3000

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

When glass fractures, cracks propagate at speeds up to 3000 mph (approximately 1.3 km/s). This rapid crack propagation is due to the release of stored elastic energy. The speed varies based on glass type, thickness, and how the break was initiated, but can approach the speed of sound in glass.