Answer:
The human ear is not sensitive to every frequency of sound, rather, our hearing range is from 20Hz to 20,000Hz. This means sound frequencies outside this range are not audible to the human ear, which is why not every sound produced is heard. This is quite a blessing because if we could hear every vibrating body, then our ears would never stop listening: we won't be able to distinguish 'important sounds' from unimportant ones, rendering our ears effectively useless. Perhaps this is why we have a hearing range in the first place: sounds of our friends and our foes lie in 20Hz-20kHz range.
Answer:
Minimum uncertainty in velocity of a proton,
Explanation:
It is given that,
A proton is confined to a space 1 fm wide, 
We need to find the minimum uncertainty in its velocity. We know that the Heisenberg Uncertainty principle gives the uncertainty between position and the momentum such that,

Since, p = mv





So, the minimum uncertainty in its velocity is greater than
. Hence, this is the required solution.
Answer:
Explanation:
Volume of block A = 10 x 6 x 1 = 60 cm³
Mass of block A = 630 g
density of mass A = mass / density
= 630 / 60 = 10.5g / cm³
Volume of block B = 5 x 5 x 3 = 75 cm³
Mass of block A = 604 g
density of mass A = mass / density
= 604 / 75 = 8.05 g / cm³
Since density of both A and B are less than that of mercury , both will float in mercury.
D) although recent research (1990's) has shown Uranus and Neptune to be ice giants and have heavier substances.
<h3>Answer</h3>
1104 km/hour
<h3>Explanation</h3>
Distance between Dallas Texas to New York = 2760 km
Time the plane took from Dallas to New York = 2 hours
Time the plane took from New York back to Dallas = 2.5 hours
Formula to use
<h3>distance = speed x time </h3>
Speed the plane took from Dallas to New York
2760 = 2 x speed
speed = 2760 / 2
= 1380 km/hour
Speed the plane took from New York to Dallas (ROUND TRIP)
2760 = 2.5 x speed
speed = 2760 / 2.5
= 1104 km/hour