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.
i think the answer is D 10.0
during satellite motion we know that total energy is always conserved
so here we will have

here we know that


now at other position

now from above equation we have

now we have


so its kinetic energy will be 3500 MJ
Direction of resultant force in circular motion is directed towards the center of the circle. Hence vector B is the direction of the resultant force.
Dark matter may explain <span>unexpected orbital velocities of stars in galaxies.</span>