Constant velocity means moving in a straight line at a speed that doesn't change. If the object is moving with constant velocity then its acceleration is zero. Acceleration is the rate at which velocity is changing.
The skier has potential because potential energy is enery that is stored or an object that is or does not move
Lithium shares more properties with Sodium, because they have the same number of valence electrons (one). Choice 1 is correct. Hope this helps!
