Explanation :
Absorption coefficient of a material determines how much sound is absorbed by the material.
To build a soundproof room, Heavy curtains and carpet can be used. They reduce reverberation.
Reverberation means an echoing sound which persists for some time. For example, when we bang on a huge piece of metal, we hear the reverberation even after we stop banging.
Hence, option (A) and (D) are correct.
No because they could be different materials for example one could be concrete and one could be aluminium
Answer:
v = 2.45 m/s
Explanation:
first we find the time taken during this motion by considering the vertical motion only and applying second equation of motion:
h = Vi t + (1/2)gt²
where,
h = height of cliff = 15 m
Vi = Initial Vertical Velocity = 0 m/s
t = time taken = ?
g = 9.8 m/s²
Therefore,
15 m = (0 m/s) t + (1/2)(9.8 m/s²)t²
t² = (15 m)/(4.9 m/s²)
t = √3.06 s²
t = 1.75 s
Now, we consider the horizontal motion. Since, we neglect air friction effects. Therefore, the horizontal motion has uniform velocity. Therefore,
s = vt
where,
s = horizontal distance covered = 4.3 m
v = original horizontal velocity = ?
Therefore,
4.3 m = v(1.75 s)
v = 4.3 m/1.75 s
<u>v = 2.45 m/s</u>
Explanation:
The nucleus of an atom is dense because it contains more of particles in a very little space.
The nucleus is the center of an atom made up of the protons and neutrons.
Atomic nucleus is very small compared to the size of the atom.
Density is function of mass and volume.
Mass is the amount of matter in a substance.
Volume is the space occupied by a substance.
The more the mass the more the density.
Since protons and neutron are massive bodies occupying a small space, they make the nucleus very dense.
learn more:
Density brainly.com/question/5055270
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