When a solid melts, A) the temperature of the substance ...

[WWatsford]

When a solid melts,
 
  A) the temperature of the substance increases.
  B) the temperature of the substance decreases.
  C) heat energy leaves the substance.
  D) heat energy enters the substance.

Question 2

Two in-phase loudspeakers are some distance apart. They emit sound with a frequency of 1536 Hz. You move between the speakers, along the line joining them, at a constant speed of 2.8 m/s.
 
  What beat frequency do you observe? The speed of sound in the room is 330 m/s.
  A) 13 Hz
  B) 431 Hz
  C) 26 Hz
  D) 4.7 Hz
  E) 118 Hz

[quynhmickitran]

Answer to Question 1

Answer: D

Answer to Question 2

Answer: C

[WWatsford]

Thanks for the timely response, appreciate it

[cici]

Gracias!