Question 17 4 Points A ball is thrown straight upward. At 5.80 m above its launch point, the ball's speed is one-half its launch speed. What is the initial speed (launch speed) of the ball? A) 7.73 m/s B 12.31 m/s 113.70 m/'S D 10.66 m/'s Question 18 4 Points A large boulder is ejected vertically upward from a volcano with an initial speed of 50.0 m/s. Air resistance maybe ignored. At what time after being ejected is the boulder moving at 25 m's upward? A 2.55 s 5.10 C 7.65 5 D 10 Question 19 4 Points A large boulder is ejected vertically upward from a volcano with an initial speed of 50.0 m/s. Air resistance maybe ignored. At what time after being ejected is the boulder moving at 25 m/'s downward? A 2.55 5 B 5.10 s C 7.65 s D 10