With this type of crossbow, a soldier could fire several shots per second, although the bolts did not travel as fast or do as much damage as a bolt shot from a steel crossbow with a crannequin. But regardless of whether it's built for strength or speed, a crossbow's basic function ...
1. Most historians hold that the Chinese invented fireworks in the 9th century when they discovered how to make gunpowder. Story has it that a Chinese cook accidentally mixed together what were then considered common kitchen items and noticed they burnt. When put tightly(紧紧地)in a bamboo ...
1. Most historians hold that the Chinese invented fireworks in the 9th century when they discovered how to make gunpowder. Story has it that a Chinese cook accidentally mixed together what were then considered common kitchen items and noticed they burnt. When put tightly(紧紧地)in a bamboo tube...
Huygens did not use the term "kinetic energy," however, as the phrase wouldn't be coined for nearly another century; he instead referred to "a quantity proportional to mass and velocity squared' [source: Hutzler, et al.]. Conservation of momentum had first been suggested by French ...