You hear a sound in the distance. suddenly the sound gets deeper, decreasing in pitch. which can you assume about the sound waves reaching your ears?
a. the wavelengths of the new sound waves are longer.
b. the amplitude of the new sound waves has increased.
c. the sound waves have changed their speed so that they are now moving more quickly through the air.

Aballet student who learns with the of his instructor is demonstrating learning.

Askydiver weighing 140 lb (including equipment) falls vertically downward from an altitude of 19,000 ft and opens the parachute after 18 s of free fall. assume that the force of air resistance, which is directed opposite to the velocity, is of magnitude 0.55|v| when the parachute is closed and is of magnitude 14|v| when the parachute is open, where the velocity v is measured in ft/s. assume that acceleration due to gravity has magnitude 32 ft/s/s; remember that weight is the product of mass and gravitational acceleration. (a) find the speed of the skydiver when the parachute opens. (b) find the distance fallen before the parachute opens. (c) what is the limiting velocity vl after the parachute opens? (d) determine how long the sky diver is in the air after the parachute opens. (e) plot the graph of velocity versus time from the beginning of the fall until the skydiver reaches the ground.

The respiratory system removes oxygen and water from the body. select the best answer from the choices provided t f