Answer:

Explanation:
It is given that,
Depth of Death valley is 85 m below sea level, 
The summit of nearby Mt. Whitney has an elevation of 4420 m, 
Mass of the hiker, m = 65 kg
We need to find the change in potential energy. It is given by :



or

So, the change in potential energy of the hiker is
. Hence, this is the required solution.
Option number three is correct energy can be transformed and moved and released but it can't be destroyed and doesn't disappear.
Answer:
f1 = 58.3Hz, f2 = 175Hz, f3 = 291.6Hz
Explanation:
lets assume speed of sound is 350 m/s.
frequencies of a standing wave modes of an open-close tube of length L
fm = m(v/4L)
where m is 1,3,5,7......
and fm = mf1
where f1 = fundamental frequency
so therefore: f1 = 350 x 4 / 1.5
f1 = 58.3Hz
f2 = 3 x 58.3
f2 = 175Hz
f3 = 5 x 58.3
f3 = 291.6Hz