Answer:
Explanation:
Given
time taken 
Speed acquired in 2 sec 
Here initial velocity is zero 
acceleration is the rate of change of velocity in a given time


Distance travel in this time

where
s=displacement
u=initial velocity
a=acceleration
t=time


so Jet Plane travels a distance of 42 m in 2 s
Question
What is the length of the pipe?
Answer:
(a) 0.52m
(b) f2=640 Hz and f3=960 Hz
(c) 352.9 Hz
Explanation:
For an open pipe, the velocity is given by

Making L the subject then

Where f is the frequency, L is the length, n is harmonic number, v is velocity
Substituting 1 for n, 320 Hz for f and 331 m/s for v then

(b)
The next two harmonics is given by
f2=2fi
f3=3fi
f2=3*320=640 Hz
f3=3*320=960 Hz
Alternatively,
and 

(c)
When v=367 m/s then

Answer:
Using wood also helps keep carbon out of the atmosphere, helping to mitigate climate change.
Deforestation.
Explanation:
Trees store carbon dioxide as they grow. After harvest, wood products continue to store much of this carbon. These benefits continue when wood is reclaimed to manufacture other products.
Extraction of wood within the supply areas clearly affects the forest and the environment. Some of these impacts can be seen in the study areas. The rainfall is increasingly irregular, biodiversity has been lost. Communities have experienced flooding and drought, which adversely affects the most important sector in the country's economy, that of agriculture. The local populations are concerned about these impacts, which affect not only the environment but the whole social economy.