Which of these follows from kepler's laws of planetary motion?
a- a satellite will slow down as it gets further from the much more massive object it orbits.
b- objects attract each other with a force proportional to the product of their masses.
c- planets closer to the sun have lower orbital speeds.
d- all planets move in circular orbits.

The passing of heat through a material while the material itself stays in place. a. radiation b. conduction c. convection

Aphoton is absorbed by an electron that is in the n = 3 state of a hydrogen atom, causing the hydrogen atom to become ionized. very far away from the nucleus, the released electron has a velocity of 750,000 m/s. what was the wavelength of the absorbed photon?

Which best describes the first law of thermodynamics as compared to the second law of thermodynamics? a. the first law describes how thermal energy is conserved but not the direction it moves. b. the first law describes the direction thermal energy moves but not how it is conserved. c. the first law describes how thermal energy can be created but not how it can be destroyed. d. the first law describes how thermal energy can be destroyed but not how it can be created.