vector is described as having magnitude 5 and angle -20°. which is an equivaent statement of magnitude and angle of vector ? (note: all angles are measured counterclockwise from the x-axis.)

magnitude 5; angle 70°

magnitude 5; angle 20°

magnitude -5; angle 20°

magnitude 5; angle 160°

magnitude -5; angle 160°

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.

Answera volcano just before it erupts