A quality of the substance that never changes and can be used to identify the substance​

Name the non metal condut electricity

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.

Ascientific blank must be testable and capable of being proven false?