Lydia is an example of an optimist. Optimists always look at the positive side of a particular situation. They believe in a positive result. Optimist always see "the bright side" as opposed to the pessimist. The word optimism comes from latin word "optimum" which means "the best".
Answer:
The water level will drop by about 1.24 cm in 1 day.
Explanation:
Here Mass flux of water vapour is given as

where
is the mass flux of the water which is to be calculated.
- D is diffusion coefficient which is given as

- l is the thickness of the film which is 0.15 cm thick.
is given as

In this
is the saturated water pressure, which is look up from the saturated water property at 20°C and 0.5 saturation given as 2.34 Pa
is the air pressure which is given as 0.5 times of 
- R is the universal gas constant as

- T is the temperature in Kelvin scale which is

By substituting values in the equation

Converting
into 
As 1 mole of water 18
so

Putting this in the equation of mass flux equation gives

For calculation of water level drop in a day, converting mass flux as

So the water level will drop by about 1.24 cm in 1 day.
Answer:
74.52s
Explanation:
The solution is shown in the picture below
I could be wrong, but I'm pretty sure it's 144kg.
Answer:
f3 = 102 Hz
Explanation:
To find the frequency of the sound produced by the pipe you use the following formula:

n: number of the harmonic = 3
vs: speed of sound = 340 m/s
L: length of the pipe = 2.5 m
You replace the values of n, L and vs in order to calculate the frequency:

hence, the frequency of the third overtone is 102 Hz