Please answer all

19. If a wave has a frequency of 440 Hz and a wave speed of 342 m/s, what is its wavelength? A. 65 cm B. 73 cm C. 78 cm D. none of the above 20. What is the beat frequency of two waves with frequencies of 258 Hz and 266 Hz? A. 2 Hz B. 4 Hz C. 6 Hz D. 7 Hz E. none of the above 21. A block of iron is totally immersed in water, with the long edge of the block vertical. The pressure on the brick is A) greatest on the face with largest area. B) greatest on the bottom of the block. C) the same on all surfaces of the block. D) greatest on the sides of the block. E) greatest on the top of the block. 22. The waves produced by the FM radio station 100.3 have a wavelength of A. 2.99 m B. 2.88m C. 3.01 m D. none of the above 23. As shown in the figure, a given force is applied to a rod in several different ways. In which case is the torque about the axis P due to this force zero? 2. 3. A) 1 B) 2 C) 3 D) 4 E) 5