9. A ball was thrown towards a cliff of height h with a speed of 30 m's at an angle of 60 above the horizontal. It lands on the edge of the cliff 4.0 s later. (a) How high was the cliff? (b) What was the maximum height of the ball? 10. A ball thrown horizontally at 25 m's travels a horizontal distance of 50 m before hitting the ground. From what height was the ball thrown? 11. Anita is running to the right at 5 m/'s. Ball 1 is thrown towards her from behind at a speed vi and ball 2 is thrown towards her from the front at a speed v2. Anita sees both balls approaching her at 10 m/s. Determine vi and v2. 12. A swimmer wishing to cross a 600 m wide river begins to swim straight across at a speed of 2.20 m/s. If the river flows at a steady speed of 0.750 m's. What is the speed of the swimmer viewed by someone at the bank?13. Through what angle will the minute hand of an analogue clock turn during a time span of 50 minutes? 14. A small ball swung in a circular path takes 12 seconds to make 20 rotations. What is the frequency of its motion? A. 0.60 Hz B. 1.67 Hz C. 240 Hz D. 12.0 Hz 15. The turntable of a music player is rotating at a rate of 80.0 rpm. The period of this rotation is 16. A small ball of mass 200 g is rotated in a horizontal circle of radius 0.5 m. If the ball makes 10 revolutions in 5 seconds, what is its centripetal acceleration? 17. An electric fan goes from rest to a speed of 1800 rpm in 4.0 s. What is its angular acceleration? 18. The moon orbits the earth in a nearly circular path once every 27.3 days. It the distance from the moon to the earth is 384,000 km, what is the moon's acceleration? 19. Calculate the velocity of a satellite moving in a stable circular orbit about the Earth at a height of 3600 km. 20. A hypothetical planet has a radius 2.5 times that of earth but has the same mass. What is the acceleration due to gravity near its surface