Picture a ball traveling a constant speed the inside of a circular structure. is the ball accelerating?

Yes it is.  The ball is undergoing accelerated motion.  Uh huh.  You bet it is.

"Acceleration" does NOT mean "speeding up". Acceleration is "change of velocity", and 'velocity' is speed AND direction.  If speed or direction changes, velocity changes, and that's 'acceleration'.

If the ball is traveling in a circle, then its direction is continually changing.  Its motion is constantly accelerated.  Even if its speed never changes.

i think it because equal matrices have equal dimensions, only square matrices can be symmetric. for all indices and . every square diagonal matrix is symmetric, since all off-diagonal elements are zero. in linear algebra, a real symmetric matrix represents a self-adjoint operator over a real inner product space.

heat the gas and measure the pressure