Aspeaker fixed to a moving platform moves toward a wall, emitting a steady sound with a frequency of 225 hz . a person on the platform right next to the speaker detects the sound waves reflected off the wall and those emitted by the speaker. part a how fast should the platform move, vp, for the person to detect a beat frequency of 7.00 hz ? take the speed of sound to be 344 m/s. express your answer

Aflask with vinegar in it has a mass of 160 grams. a balloon with baking soda in it has a mass of 40 grams. the balloon is attached to the flask to seal the opening and the vinegar and baking soda mixes. the balloon inflates to a large volume. what will the total mass of the balloon and flask be after the balloon inflates? explain. a) less than 200 grams because the solid baking soda disappears. b) 200 grams, because all the atoms remain in the balloon or flask. c) more than 200 grams because the size of the balloon is so much larger. d) less than 200 grams because gases such as the one in the balloon are lighter than solids and liquids.