The "coefficient of absorption" of a soundproofing material is
the fraction of sound energy that goes into the material, gets
absorbed, doesn't come out, and is never heard again.
So, sample C would be the best choice, because the percentage
of the energy in an incident wave that gets absorbed in this material
is the greatest, and the percentage of the energy that remains in a
reflected wave from this material is the smallest. (Choice-B)
The answer to the question is b
10.4 N
Given
m = 1.10 kg
θ = 15.0°
g = 9.81 m/s2
Solution
Fnet, y = ΣF y = Fn − Fg, y = 0
Fn = Fg, y = Fg
cosθ = mgcosθ
Fn = (1.10 kg)(9.81 m/s2
)(cos15.0°) = 10.4 N
Answer:
B. 102,900 N
I remember this question from one of my, test. Really hope this helps..
Answer:
0.71 m/s
Explanation:
We find the time it takes the stone to hit the water.
Using y = ut - 1/2gt² where y = height of bridge, u = initial speed of stone = 0 m/s, g = acceleration due to gravity = -9.8 m/s² (negative since it is directed downwards)and t = time it takes the stone to hit the water surface.
So, substituting the values of the variables into the equation, we have
y = ut - 1/2gt²
82.2 m = (0m/s)t - 1/2( -9.8 m/s²)t²
82.2 m = 0 + (4.9 m/s²)t²
82.2 m = (4.9 m/s²)t²
t² = 82.2 m/4.9 m/s²
t² = 16.78 s²
t = √16.78 s²
t = 4.1 s
This is also the time it takes the raft to move from 5.04 m before the bridge to 2.13 m before the bridge. So, the distance moved by the raft in time t = 4.1 s is 5.04 m - 2.13 m = 2.91 m.
Since speed = distance/time, the raft's speed v = 2.91 m/4.1 s = 0.71 m/s
