Select all that apply. which of the following astronomers supported the earth-centered system? tycho brahe kepler copernicus ptolemy

What would the difference of spectral lines emitted by hydrogen gas in distant galaxies which is normally found at a wavelength of 21 cm on earth, be observed at 21.1 centimeters?

The car hoist allows the car to be driven onto the platform, after which the rear wheels are raised. if the loading from both rear wheels is 1380 lb, determine the force in the hydraulic cylinder ab. neglect the weight of the platform itself. member bcd is a right-angle bell crank pinned to the ramp at c. the force is positive if in tension, negative if in compression.

Abicycle slows down when the rider applies the brakes. what type of energy transformation is involved in this example? a. kinetic energy into heat energy b. heat energy into potential energy c. potential energy into kinetic energy d. kinetic energy into mechanical energy