A circus performer walked up and to the right for a total displacement of 10\,\text m10m10, start text, m, end text along a diagonal tightrope angled 30 \degree30°30, degree above the ground.

  concave means having an outline or surface that curves inward like the interior of a circle or sphere. so the mirror curves inward.

Sounds propagates through some kind of medium. usually it's air, but it goes just as well through solid objects like walls, windows etc. a soundwave will compress the (air)molecules in front of it, and if this increased density wave hits your ears, you register it as sound. solid objects like walls are a lot denser than air, this means that they will damp a wave, but also carry it easier.