How did people studying lunar eclipses learn that Earth is round? (A) They observed Earth's shadow on the moon.
(B) They observed the moon's shadow on Earth.
(C)
(D)
They observed that lunar eclipses can last for hours.
They observed that solar eclipses are shorter than lunar eclipses.

The dissociation energy of a molecule is the energy required tobreak apart the molecule into its separate atoms. the dissociationenergy for a particular molecule is 5.48 x 10-18 j.suppose that this energy is provided by a single photon. determinethe (a) wavelength and (b) frequency of the photon

Choose the most likely outcome of this scenario: jen decided to go bike riding without a helmet. while no one is around during her ride, she is thrown from her bike when her wheel goes into a pothole. she is not injured, but she is terrified to get back on her bike. what happens next? a. her physical health is affected even though she wasn't hurt. b. her mental and emotional health are affected because she is afraid to get back on her bike. c. her social health is affected because she is worried her friends saw the fall. d. her overall health is not affected at all by her fall.

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