Cobalt is a radioactive substance used in nuclear medicine. You are given an old souce of radioactive cobalt with 4.2 ng of cobalt-60 written on it to analyze. You determine that the present diation of this sample is 182 Bq. What is the Age of this source in years? What quantity, in grams, of cobalt-60 is left in this source?

The speed of sound in ice, water, and steam is shown. what best explains the speed of sound in different states of matter? sound travels fastest in ice because energy is easier to transfer when the molecules are close together. sound travels slowest in steam because the sound has to move around the gas molecules that are far apart. sound travels fastest in ice because the temperature of solids is always greater, so the heat transfers the sound energy. sound travels slowest in steam because the pressure is so great the sound cannot travel though the steam particles.

Aball is thrown from the top of a building with an initial velocity of 21.9 m/s straight upward, at an initial height of 51.6 m above the ground. the ball just misses the edge of the roof on its way down, as shown in the figure. (a) determine the time needed for the ball to reach its maximum height. (b) determine the maximum height. (c) determine the time needed for the ball to return to the height from which it was thrown, and the velocity of the ball at that instant. (d) determine the time needed for the ball to reach the ground. (e) determine the velocity and position of the ball at t = 5.35 s.

Asatellite with an orbital period of exactly 24.0 h is always positioned over the same spot on earth. this is known as a geosynchronous orbit. television,communication, and weather satellites use geosynchronous orbits. at what distance would a satellite have to orbit earth in order to have a geosynchronous orbit?