Answer:
soundproofing or absorbing
Explanation:
Acoustics is the study of waves, vibrations and sound and its most common applications lie in the sound and noise control industries. Acoustic protection is the application of soft and porous material to protect individuals against undesirable sounds and noises.
cushioned seats and carpeted floors are used in soundproofing to block the unwanted noise and sound.
The Cheapest Ways To Soundproof A Room
1. Rugs:
Rugs make excellent vibration dampeners.
2. Weather Stripping:
If you know that sound is getting into your room via the door or the windows then a very cheap and effective solution can be to use weather stripping.
3. Blankets.
4. Curtains.
5. Egg Cartons.
Homemade Soundproofing Panels
Hi there!
On a level road:
∑F = Ff (Force due to friction)
The net force is the centripetal force, so:
mv²/r = Ff
Rewrite the force due to friction:
mv²/r = μmg
Cancel out the mass:
v²/r = μg
Solve for v:
v = √rμg
v = √(25)(9.81)(0.8) = 14.01 m/s
Here in all such collision type question we can use momentum conservation as we can see that there is no external force on this system

as we know that




now from above equation we have



so the speed of combined system is 2 m/s
C because the the smallest thing then the other ones because it never said what kind of size of it