What was Edwin Hubble's contribution to the field of astronomy? A. He discovered variable stars.
B. He proved that the heliocentric model accurately described our solar system. C.
He found a relationship between the period luminosity and distance of stars. D.
He proved that the universe is finite.
E.
He discovered that the universe was expanding.

Sawyer is studying diffraction. he draws a diagram of a plane wave to show how light waves travel. which best describes sawyer’s error? the wave fronts should be perpendicular to the direction in which the waves move. the arrow showing the direction of movement of the waves should be pointing to the left. the arrow showing the direction of movement of the waves should be pointing downward. the wave fronts should be both parallel and perpendicular to the direction in which the waves move.

Which of these is the best way to manage a natural resource

Why does the equilibrium position of the spring change when a mass is added to the spring? will the mass oscillate around the new equilibrium position of the spring or the previous position without a mass attached to the spring? if the equilibrium position of the spring changes by 20 cm (assuming no initial mass) when a mass is added to the spring with constant 4.9 kg/s^2, what is the mass of the object attached to the spring?