2. in the history of astronomy, which of the following is true? (2 points) ptolemy was criticized for his work on the heliocentric model. nicolaus copernicus could not prove that the sun was the center of the universe. johannes kepler argued that earth was the center of the universe. tycho brahe built one of the first observatories.

On your wedding day your lover gives you a gold ring of mass 3.67 g. 48 years later its mass is 3.44 g. on the average how many atoms were abrated from the ring during each second of your marriage? the atomic mass of gold is 197 u. don't enter units

An electron moves with a constant horizontal velocity of 3.0 × 106 m/s and no initial vertical velocity as it enters a deflector inside a tv tube. the electron strikes the screen after traveling 26 cm horizontally and 19 cm vertically upward with no horizontal acceleration. what is the constant vertical acceleration provided by the deflector? (the effects of gravity can be ignored.)

During the apollo moon missions, astronauts were concerned about the effects of newton's third law of motion when: o a. they ejected waste water, because they were concerned that it would push them off course. o b. they reentered earth's atmosphere, because they were carrying heavy moon rocks. o c. they took off from earth, because a large force was required to generate large acceleration. o d. they detected incoming space debris, because the inertia of the debris could damage their ship.