Final answer:
An object at rest or in motion with respect to a frame of reference, regardless of its mass or size, has a momentum of zero with respect to that frame of reference.
Step-by-step explanation:
An object at rest or in motion with respect to a frame of reference, regardless of its mass or size, has a momentum of zero with respect to that frame of reference. This is because momentum is defined as the product of an object's mass and velocity, and if the object is not moving or is moving at a constant velocity, its momentum will be zero.
For example, consider a car parked on the side of the road. Since it is not moving, its velocity is zero and therefore its momentum is also zero with respect to the frame of reference of the road.
Similarly, if a train is moving at a constant velocity on a straight track, its momentum with respect to an observer standing still on the ground will also be zero.