Enter your Name:   Enter your E-mail Address:  Be sure to write all your answers with the proper number of significant figures and to list the units that go with your answers! (G = 6.67 x 10-11 , Mass of sun = 2.0 x 1030kg, Mass of earth = 5.98 x 1024kg) 01. Several physical characteristics are listed below. Which do not change in uniform circular motion? a. velocity   b. speed   c. centripetal acceleration   d. magnitude of the centripetal acceleration e. cintrepetal force     f. magnitude of the centripetal force 02. An object moves in a circle with constant speed as pictured below. Draw in the velocity, acceleration, and force vectors. 03. If an object is moving in a circle but its speed varies, is there still a centripetal force acting on the object? 04. If an object is moving in a circle at a constant speed and suddenly its speed decreases by a factor of two, how must the centripetal acceleration change to keep the object moving in the same circle? 05. If two massive objects were placed near each other on a frictionless surface, what would happen? 06. In a physics experiment, two objects were placed a certain distance apart and their gravitational attraction was measured. Afterwards, the distance between them was decreased by a factor of 4. What happened to the gravitational force between them when the distance was changed? 07. Why do the planets orbit the sun in nearly circular orbits? 08. Two satellites of equal mass orbit the earth. The speed of the first satellite is 30% greater than the speed of the second. Which orbits the earth at the higher altitude? 09. During a test drive, a car is driven at a constant speed in a circle of radius 31.0 meters. If the car is traveling at 25.0 m/sec, what centripetal acceleration is required to keep the car traveling in the circle? 10. In the problem above, what is the period and frequency of the car's motion? 11. A car is turning on a curve whose radius of curvature is 23.1 meters. If the car is traveling at 13 m/sec, what is the minimum coefficient of kinetic friction necessary to keep the car on the road? 12. Two objects of equal mass exert a gravitational force of 12.1 Newtons on each other when they are 15 cm apart. Determine the mass of each object. 13. Venus orbits the sun at a distance of 1.1 x 1011 meters. How fast does it travel in its orbit? 14. The rings of Saturn are actually composed of small rocks, presumably from a moon that was crushed by a catastrophic event. If the orbital radius of one of those rocks is 6.1 x 107 meters, what is the rock's orbital period? (mass of Saturn = 5.7 x 1026 kg) 15. A satellite orbits the earth with a speed of 9.4 x 102 m/sec. What is its orbital period?