Il A heavy ball with a weicht of 100 N (m 10.2 kg) is hung. from the ceiling of a lecture hall on a 4.5-m-long rope. The ball. is pulled to one side and released to swing as a pendulum, reach-. ing a speed of 5.5 m/s as it passes throuoh the lowest point.
Inventions. The huochong gun was invented in China during the Ming dynasty. It was also called the tongjiangjun, which meant bronze general. This was an important invention of the time period because the Ming Dynasty was creating weapons to defend their dynasty, and they came across the gun.t was also called the tongjiangjun, which meant bronze general. This was an important invention of the time period because the Ming Dynasty was creating weapons to defend their dynasty, and they came across the gun.
The color printing was invented in the Ming Dynasty, the first type of printing in the world. The use of two-color printing began in the Song Dynasty (960 A.D-279 A.D). By the Yuan Dynasty, two color printing was used to print books, and it later became three and four-color printing. The color printing was invented in the Ming Dynasty, the first type of printing in the world.