Two loudspeakers placed next to each other each emit a pure tone with the same amplitude. One speaker emits a tone with a frequency of 405.0 Hz, the other with a frequency of 410.0 Hz. A distant listener perceives a pure tone that has a single frequency, but varies in loudness with a perceived "beat." (a) What is the frequency (in Hz) of the pure tone perceived by the listener? (Round your answer to at least the nearest integer.) Hz
(b) What is the beat frequency (in Hz) perceived by the listener? Hz

What are the phases shown in a and d called?

A58-kg boy swings a baseball bat, which causes a 0.140-kg baseball to move toward third base with a velocity of 38.0 m/s.

How many milliliters of water at 23 °c with a density of 1.00 g/ml must be mixed with 180 ml (about 6 oz) of coffee at 95 °c so that the resulting combination will have a temperature of 60 °c? assume that coffee and water have the same density and the same specific heat. how much will the temperature of a cup (180 g) of coffee at 95 °c be reduced when a 45 g silver spoon (specific heat 0.24 j/g °c) at 25 °c is placed in the coffee and the two are allowed to reach the same temperature? assume that the coffee has the same density and specific heat as water. a 45-g aluminum spoon (specific heat 0.88 j/g °c) at 24 °c is placed in 180 ml (180 g) of coffee at 85 °c and the temperature of the two become equal. (a) what is the final temperature when the two become equal? assume that coffee has the same specific heat as water. (b) the first time a student solved this problem she got an answer of 88 °c. explain why this is clearly an incorrect answer.