Author Question: Michael is going to the store 6 miles away. He rides his bike at 12 mph for the first half of the ... (Read 98 times)

scienceeasy · **on:** Jul 28, 2018

Michael is going to the store 6 miles away. He rides his bike at 12 mph for the first half of the trip, then walks at 4 mph for the remainder.
Michael's average speed for the trip to the store is closest to:

1.2 mph
2.4 mph
3.6 mph
4.8 mph
5.10 mph
6.12 mph
7.14 mph
8.exactly halfway between two of the values above
9.impossible to determine

Question 2

Which of the following is not one of the Bohr postulates?
1.The laws of classical physics apply to orbital motion of the electrons but not during transitions from one orbit to another.
2.The possible energies that the electron can have are discrete and depend on the orbit radius.
3.Electrons emit electromagnetic radiation only during transitions between orbits and not while in an allowed orbit.
4.Permissible orbits have an angular momentum which is an integer multiple of h/2.
5.The frequency of the radiation emitted during a transition is related to the energy difference between the orbits by f = E/h.