Question

Can an object have zero velocity but nonzero acceleration? can it have zero acceleration and nonzero velocity? WHY?

Answer 1

An object can have zero acceleration and nonzero velocity when it's moving at a constant velocity by newton's first law. Think about a car when it's moving. If it's going at a constant 40mph in a straight line then it has velocity but no acceleration.
However, if an object has zero velocity then it by default has zero acceleration. You can think about the equations for position, velocity, and acceleration in this case. Since acceleration is the derivative of velocity, if velocity is zero, the derivative of zero is also zero therefore the acceleration would be zero.