An artificial earth satellite of mass m is circling around the earth in an orbit of radius R. If the mass of the Earth is M, then the told energy of the satellite is (a) 3GMm/2R (b) -GMm/2R (c) GMm/2R (d) -GMm/R​

You can estimate the degree to which a bond between two atoms is ionic or covalent by calculating the

The radioactive isotope of lead, pb-209, decays at a rate proportional to the amount present at time t and has a half-life of 3.3 hours. if 1 gram of this isotope is present initially, how long will it take for 80% of the lead to decay? (round your answer to two decimal places.)

The center of the milky way most likely contains a. empty space. b. a red giant star. c. a globular cluster. d. a supermassive black hole.