Final answer:
The kite changes direction and speed due to unbalanced forces caused by the wind. This involves a combination of lift, gravity, tension, and air resistance, which varies with the wind's fluctuations.
Step-by-step explanation:
The question posed relates to the changes in speed and direction of a kite flown by Archie due to wind. The correct answer is a) The forces acting on the kite are unbalanced. Flying a kite involves several forces: lift generated by the wind, gravity pulling the kite down, the tension from the string, and air resistance (drag) opposing the kite's motion. The kite changes speed and direction when the magnitude or direction of these forces change, resulting in an unbalanced force situation. For example, if the wind increases, the lift on the kite might temporarily exceed the other forces, causing the kite to rise or accelerate in the direction of the wind. If there's a sudden gust or change in wind direction, the unbalanced forces will cause the kite to move accordingly.
To illustrate the forces acting on a kite floating stationary in the air, one would draw a free-body diagram with arrows representing the forces of gravity, tension in the string, lift, and drag. In this free-body diagram, these forces would typically be balanced if the kite is stationary, but in the scenario described, the forces are unbalanced, causing the kite's changes in motion.