The change in pitch of a train's horn as it passes while you are standing still can be explained by
a. resonance.
b. the doppler effect.
c. sympathetic vibration.
d. ultrasonic vibrations.

Athin, square metal plate measures 14 cm on each side and has emissivity of 0.60. the plate is heated to a temperature of 745°c. what is the rate at which the plate radiates energy ? the stefan-boltzmann constant is 5.67 × 10-8 w/(m2 ? k4). remember that the plate will radiate energy from both its top and bottom surfaces.

Astone dropped into a well is heard to strike the water after 8seconds. find the depth of the well if the velocity of sound is 350m/s

Arock collection comes from which part of earth?