Which scenario represents an unbalanced force?

A. a person jumping

B. a vase sitting on a table

C. a car driving at a constant velocity

D. an airplane flying at constant altitude and velocity

A. A person Jumping represents an unbalanced force.

Explanation:

If equal amount of force applied on any object from both the directions, then the object will not move and so the force is a balanced force.

If an unequal amount of force on an object from both sides then the object will move in the opposite direction of the maximum force applied, so it is called as an unbalanced force.

When the force is unbalanced then its velocity will change, so options C and D are omitted. In Option B the vase is sitting on a table, just kept so there is no action of any unbalanced force. But a person jumping represents an unbalanced force, since the person do not jump with constant velocity and it will vary.