Philip creates a continuous wave in a slinky with a frequency of 45 crests per second. The wavelength is 15 cm. What is the wave speed? 0.11 m/s 0.20 m/s 9.0 m/s 6.75 m/s Question 29 (Mandatory) (1 point) Shuang throws a water balloon down with a speed of 2 m/s from the roof of the school, height 20 m. What is the velocity of the balloon as it strikes the ground? 19.8 m/s 19.9 m/s O 20.2 m/s O 20.3 m/s