Where is the potential energy equal to zero?

Truck traveling west on the highway experiences an acceleration to the east. what could be the cause of this acceleration

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.

When electrons are added to the outermost shell of a carbon atom, it forms--an anion that has a larger anion that has a smaller cation that has a larger cation that has a smaller radius.