The difference between true north and magnetic north is called "declination."
Answer:
khoảng cách = 8km / h
Explanation:
khoảng cách = tốc độ / thời gian
khoảng cách = 12/40
khoảng cách = 8km / h
Answer:
Explanation:
English alphabets numbered fro 1 to 26
and the numbers 1 to10 so they are written in roman numbers as
1 - I
2 - II
3 - III
4 - IV
5 -V
6 - VI
7 -VII
8 - VIII
9 - IX
10 -X
11 - XI
12 - XII
13 - XIII
14 - XIV
15 - XV
16 - XVI
17 - XVII
18 - XVIII
19 - XIX
20- XX
21 - XXI
22 - XXII
23 - XXIII
24 - XXIV
25 - XXV
26 - XXVI
Answer:
a) 3000 Hz;
b) 30 dB;
c) 1000 times.
Explanation:
a) From the human audiogram given on the figure below the black line represents the threshold for hearing the sound at each frequency. We see that the least intensity is necessary for the frequency of about 3000 Hz.
b) Using the same audiogram we see that we would need the sound of the intensity of about 30dB.
c) The least perceptible sound at 1000 Hz must be 0dB while at 100 Hz it is 30dB. These are logarithmic quantities. To transform them to the linear quantities we use the formula

where
is the hearing threshold at 1000 Hz.
Therefore we have the following

is the threshold at 1000Hz and
is the threshold at 100Hz.
By exponentiating we have

Now dividing these two equations we get

Therefore, the least perceptible sound at 100Hz is 1000 times more intense than the least perceptible sound at 1000Hz.
Note: I got these values unisng the audiogram that is attached here. The one that you have might be slightly different and might yield different answers.
<u>Answer:</u>
average velocity =
<u>Explanation:</u>
We can find the average velocity using the following equation:
.
In this case:
• total distance travelled = 450 km
• time taken = 30 min = 0.5 h
Substituting these values into the equation:

⇒