Ascientist is performing an experiment on a powder. which of the following is a sign that a chemical change has definitely occurred during his experiment? the powder catches on fire.
the powder releases bubbles.
the powder heats up.
the powder breaks apart into smaller particles.

Aclarinetist, setting out for a performance, grabs his 3.350 kg clarinet case (including the clarinet) from the top of the piano and carries it through the air with an upward force of 24.65 n. find the case's vertical acceleration. indicate an upward acceleration as positive and a downward one as negative.