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.
Notable advances in civil engineering, nautics, and metallurgy were made in Song China, as well as the introduction of the windmill to China during the thirteenth century. These advances, along with the introduction of paper-printed money, helped revolutionize and sustain the economy of the Song dynasty.