Because of the doppler effect, the sound heard by an observer listening to a moving ambulance siren, compared to what the observer would have heard if the observer and siren were both at

a. will have a lower frequency if the ambulance siren is moving towards the observer
b. will have a higher frequency if the ambulance siren is moving away from the observer.
c. will have a higher frequency if the ambulance siren is moving towards the observer.
d. will have a lower pitch if the ambulance siren is moving towards the observer.
e. will have a longer wavelength if the ambulance siren is moving towards the observer.

Researchers determine that the biodiversity in a woodland region is declining. they identify two major threats to the region's biodiversity, a method to address each threat, and the expected outcome of each method. this information is shown in the table. a) reforestation would not benefit many species because most forest species live on the ground. b) reforestation would take the longest time to be effective because trees take several years to grow. c) biological augmentation would benefit only a few species because is is typically not very effective. d) biological augmentation would take less time to ve effective because it targets the majority of prey species.

Match each vocabulary term to its definition. 1. electrons neutral subatomic particles found in the nucleus of the atom 2. neutron lowest energy position of an electron in an atom 3. photon the path of an electron around the nucleus of an atom 4. ground state negatively charged, subatomic particles 5. protons packet of energy of specific size 6. element substance with only one type of atom 7. orbital positively charged, subatomic particles found in the nucleus of the atom

A14 kg rock starting from rest free falls through a distance of 5.0 m with no air resistance. find the momentum change of the rock caused by its fall and the resulting change in the magnitude of earths velocity. earth mass is 6.0 * 10^24 kg. show your work assuming the rock earth system is closed.