Potential energy is first transformed into kinetic energy as she pedals, then gravitational as she coasts down the hill.
3 rd one because I had this on my test
Answer:
20.7 billion = 20.7E9 converting to units of 10
20.7E9 km = 20.7E12 m
t = S /v = 20.7E12 m / 3.0E8 m/s = 6.9E4 s = 69000 s
69000 s = 1150 min = 19.2 hrs
