Molecular Physics | Thermodynamics Answers

A sound pulse emitted underwater reflects off a school of fish and is detected at the same place
0.15 s
later (see the figure below). How far away are the fish? (Assume the water temperature is 20°C.)

The sound level measured in a room by a person watching a movie on a home theater system varies from
60 dB
during a quiet part to
90 dB
during a loud part. Approximately how many times louder is the latter sound?

A 3.2 Hz continuous wave travels on a Slinky. If the wavelength is 0.49 m, what is the speed of waves on the Slinky (in m/s)?

Two children stretch a jump rope between them and send wave pulses back and forth on it. The rope is 2.7 m long, its mass is 0.46 kg, and the force exerted on it by the children is 37 N.

(a)
What is the linear mass density of the rope (in kg/m)?



(b)
What is the speed of the waves on the rope (in m/s)?

An audio speaker producing a steady sound at an outdoor concert is 18 ft away from you. If you move to a position where the speaker is 81 ft distant, by what factor will the amplitude of the sound change?
Af
Ai
=

From a cylinder with a pressure of 60 bar and a volume of 40 l, a quantity of gas is withdrawn which, at an air pressure of 1 bar, has a volume of 80 l. Calculate the pressure in the bottle after the gas has been removed, if the temperature during the process remains constant

A 17-kg piece of metal displaces 2.0 L of water when submerged. Find its density.

An apartment has the dimensions 17 m by 9 m by 6 m. The temperature is 20°C, and the relative humidity is 50 percent. What is the total mass (in kg) of water vapor in the air in the apartment?

An aluminum wing on a passenger jet is
40 m
long when its temperature is
19°C.
At what temperature would the wing be 6 cm (0.06 m) shorter?

A machinist wishes to insert an iron rod with a diameter of 2 mm into a hole with a diameter of 1.995 mm. By how much would the machinist have to lower the temperature (in °C) of the rod to make it fit the hole?