1. [l5 Points] DETAILS OSCOLPHYSZO16 6.3.P.023. MY NOTES ASK YOUR TEACHER (a) A 15.0 kg child is riding a playground merry-goround that is rotating at 50.0 rev/min. What centripetal force (in N) must she exert to stay on if she is 2.50 m from its center? 1.02610A3 N (b) What centripetal force (in N) does she need to stay on an amusement park merrygoround that rotates at 3.00 rev/min if she is 8.00 m from its center? 0786 N (c) Compare each force with her weight. force from (a) weight force from (b) weight 3. [/5 Points] DETAILS OSCOLPHYSZO16 6.6.P.047. MY NOTES ASK YOUR TEACHER Astronomical observations of our Milky Way galaxy indicate that it has a mass of about 8 x 1011 solar masses. A star orbiting near the galaxy's periphery is 5.9 x 104 light years from its center. (a) What should the orbital period (in y) of that star be? 5.55e10"10 y (b) If its period is 6.7 x 107 y instead, what is the mass (in solar masses) of the galaxy? Such calculations are used to imply the existence of "dark matter" in the universe and have indicated, for example, the existence of very massive black holes at the centers of some galaxies. 6.0910A11 solar masses 4. [0/5 Points] DETAILS PREVIOUS ANSWERS OSCOLPHYSZO16 6.6.P.048. MY NOTES ASK YOUR TEACHER Space debris left from old satellites and their launchers is becoming a hazard to other satellites. (a) Calculate the speed in m/s of a satellite in an orbit 800 km above the Earth's surface. 7,662 x m/s (b) Suppose a loose rivet is in an orbit of the same radius that intersects the satellite's orbit at an angle of 90 relative to Earth. What is the velocity in m/s of the rivet relative to the satellite just before striking it? (Enter the magnitude.) 10,834 X m/s (c) Given the rivet is 2.00 mm in size, how long in seconds will its collision with the satellite last? (Assume the rivet is flattened like a pancake on the surface of the satellite during the collision.) 1.30e10A3 x Your answer cannot be understood or graded. More Information 5 (d) f its mass is 0.700 9, what is the average force in newtons it exerts on the satellite? (Enter the magnitude.) 6.58 X N (e) How much energy in joules is generated by the collision? (The satellite's velocity does not change appreciably, because its mass is much greater than the rivet's.) 5.5910A4 X Your answer cannot be understood or graded. More Information J