Answer:
c. nine times as low.
Explanation:
Sound intensity is defined as the acoustic power transferred by a sound wave per unit of normal area to the direction of propagation:
Since the sound wave has a spherical wavefront of radius r, then the area is given by:
Here r is the distance from the source of the sound. Thus sound intensity decreases as:
Answer:
a = 52s²
Explanation:
<u>How to find acceleration</u>
Acceleration (a) is the change in velocity (Δv) over the change in time (Δt), represented by the equation a = Δv/Δt. This allows you to measure how fast velocity changes in meters per second squared (m/s^2). Acceleration is also a vector quantity, so it includes both magnitude and direction.
<u>Solve</u>
We know initial velocity (u = 16), velocity (v = 120) and acceleration (a = ?)
We first need to solve the velocity equation for time (t):
v = u + at
v - u = at
(v - u)/a = t
Plugging in the known values we get,
t = (v - u)/a
t = (16 m/s - 120 m/s) -2/s2
t = -104 m/s / -2 m/s2
t = 52 s
Answer:
160 m
Explanation:
The intensity, I, of the sound is inversely proportional to the square of the distance, r, from the source.
Hence,
From the question, 
is half of 
Average speed = (total distance covered) / (time to cover the distance)
Total distance = (77km + 66km) = 143 kilometers
Time to cover the distance = 2 hours
Average speed = (143 km) / (2 hours) = 71.5 km per hour
