Why is the standard system of measurement important?
a) each country wants is own set of measurement standards
b) scientists want to share measurement data so they can understand
c) measurements are seldom shared with scientists in other country's
d) scientists speak many different languages

4. who was the first one to measure the speed of light and conclude that it is finite? 5. who was the first philosopher who thought the speed of light is finite? 13. what is the speed of light numerically? 14. give an example of something moving faster than light 15. give an example for some particles or waves that

The boy of mass 30 kg is at r1= 2 meters from the fulcrum. of the girl is 45 kg, at what r2 must she sit so that they are balanced ?

At what time will the interfering waves have an amplitudeof zero?