Observational studies are a prime example. Observational data is more reflective of the real environments that scientists make their inferences to than controlled experiments. The disadvantage of observational studies is that the variability is far greater. <span />
No, it can also be less than 1 depending on the class of the lever.
Explanation:
The runner was 8.6km away from the finish line when the bird starts flying.
Therefore it takes the bird 8.6/14.4 = 0.60 hours for the bird to fly to the finish line.
In that 0.60 hours, the runner would have ran an extra 3.6km/h * 0.6h = 2.16km.
Now, the runner and the bird are flying towards each other. The distance between them is 8.6 - 2.16 = 6.44km and their combined speed is 18.0km.
Hence, they will meet in 6.44/18.0 = 0.36 hours.
Overall, the bird flew for 0.60 + 0.36 = 0.96 hours, and flew 14.4km/h * 0.96h = 13.8km.
Metals are goods conductors of electricity because the electrons in the electrons sea are free to flow and carry electric currents. Metals are ductile and malleable because local bonds can be easily broken and reformed.
