Question

the diagram shows an inflated balloon attached to a straw that is moving along a string. some forces that are acting on the straw are shown. what causes the balloon to move along the string? force from the string friction between the string and straw force from the escaping air weight of the balloon containing air

Explanation:

According to Newton's third - law of motion, when air escapes from the balloon, it exerts a force in one direction, and the balloon experiences an equal and opposite reaction force, causing it to move along the string. The force from the string acts as a guide, the friction opposes the motion, and the weight acts downwards. The force from the escaping air is the driving force for the balloon's motion along the string.

Answer:

force from the escaping air