Arm's length) ol rädius 0.0 discus. 12. 5. (ii) suppose the space shuttle is in orbit 400 km from the earth's surface, and circles the earth about once every 90 minutes. find the centripetal acceleration of the spac shuttle in its orbit. express your answer in terms of g, the gravitational acceleration at the earth's surface. 6. (ii) what is the magnitude of the acceleration of a speck of clay on the edge of a potter's wheel turning at 45 rpm (revolutions per minute) if the wheel's diameter is 32 cm? 7. (ii) a ball on the end of a string is revolved at a uniform rate in a vertical circle of radius 72.0 cm, as shown in fig. 5-33. if its speed is 4.00 m/s and its mass is 0.300 kg, calculate the tension in the string when the ball is (a) at 13. the top of its path, and (b) at the bottom of its path. tl