Final answer:
Momentum of an object at any given time depends on its mass and its velocity, which includes both speed and direction; it is a vector quantity with SI unit kg.m/s.
Step-by-step explanation:
At any given time, the momentum of an object depends upon its mass and its velocity. Momentum is defined as an object's mass times its velocity. The velocity factor of momentum includes both the speed and direction of the object's motion. For instance, if an object is moving south at 20 kilometers per hour, its velocity would be 20 kilometers per hour south, not merely the speed. Momentum, represented by the symbol p, is a vector quantity, which means it has both magnitude and direction, and is directly proportional to both the object's mass and velocity. It's important to note that momentum is different from kinetic energy, which depends on the square of the velocity. The SI unit for momentum is kg·m/s.
For example, a large truck moving quickly has a much greater momentum than a small, slow-moving bike. This is because the truck's large mass and high velocity contribute to a higher product of mass times velocity, hence greater momentum.
Additionally, the change in momentum of an object is proportional to the force applied and the time duration over which the force is applied. This relation is critical when studying dynamics and plays a vital role in the understanding of motion and collisions.