Decades: 1120s 1130s 1140s 1150s 1160s - 1170s - 1180s 1190s 1200s 1210s 1220s
Years: 1173 1174 1175 1176 1177 - 1178 - 1179 1180 1181 1182 1183
Births
Deaths
... start rotating perpendicular to the force applied. This is why spinning gyro tops will not simply fall over, but start precessing around. (The precessing motion is ...