Where should you place an object on the principal axis in front of a convex mirror to get a virtual, upright, and smaller image?
a anywhere on the principal axis
b only at the focal point on the principal axis
c only between the center of curvature and the focal point on the principal axis
d only between the focal point and the vertex on the principal axis
e only at the center of curvature on the principal axis

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me

= initial pressure

= final pressure = 2

= initial volume

= final volume = /4

= initial temperature = 20 c = 20 + 273 = 293 k

= final temperature = ?

using the equation