Is a exothermic a reaction that absorbs energy

Hydrogen and helium are both members of?

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.

How to know which equation of motion to use where?explain