Answer:
-56.9 m/s
Explanation:
Given:
Δy = -165 m
v₀ = 0 m/s
a = -9.8 m/s²
Find: v
v² = v₀² + 2aΔy
v² = (0 m/s)² + 2 (-9.8 m/s²) (-165 m)
v = -56.9 m/s
Answer:
<em>The total time is: t=451.22 sec</em>
<em>The average speed is: V=34.57 m/s</em>
Explanation:
<u>Average speed</u>
The average speed is calculated by dividing the total distance traveled by an object (x) by the total time it took it to travel that distance (t).

Since the student makes the trip in two parts, we have to calculate the total distance and the total time.
We know the distance to school is 7.8 Km = 7,800 m. The student makes his way home over the same distance, thus the total distance is
x=2*7,800 m=15,600 m
The first trip to school was done at an average speed of v1=32.6 m/s. Knowing the distance and speed, we can calculate the time:

The second trip back home was done at an average speed of v2=36.8 m/s. Let's calculate the second time:

The total time is:


The average speed is:


You'll get destructive interference if both waves are the same frequency but the peaks of one wave overlap the troughs of the other wave.
That can only happen if one wave has to travel (1/2 wavelength) farther than the other one to reach your ears. So we want to find the lowest frequency for which 52 cm is 1/2 of a wavelength ... the wavelength is 104 cm.
Frequency = (speed) / (wavelength)
Frequency = (344 m/s) / (104 cm)
Frequency = (344 m/s) / (1.04 meter)
Frequency = (344 / 1.04) per second
Frequency = 330.8 Hz .
B) It’s material moves due to convection currents.