Science, Maths & Technology
IT: Information
...Système International. The SI unit for length is the metre and for time is the second. In SI units, therefore, speed is expressed as metres per second. There is more about SI units in The Sciences Good Study Guide (Northedge et al., 1997). Activity 30 For a communications satellite to be in a geostationary orbit it has to be about 36,000 km above the Earth. How much...