The best evidence for a black hole at the center of the galaxy also comes from the application of kepler’s third law. suppose a star at a distance of 20 light-hours from the center of the galaxy has an orbital speed of 6200 km/s. how much mass must be located inside its orbit?

Suppose a force of 60 n is required to stretch and hold a spring 0.1 m from its equilibrium position. a. assuming the spring obeys hooke's law, find the spring constant k. b. how much work is required to compress the spring 0.5 m from its equilibrium position? c. how much work is required to stretch the spring 0.6 m from its equilibrium position? d. how much additional work is required to stretch the spring 0.1 m if it has already been stretched 0.1 m from its equilibrium? a. kequals 600