What Causes a Reel to Reverse Direction When Pulled?

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When a string is pulled perpendicularly from a reel on a flat surface, the reel initially rolls away from the string. As the angle between the string and the surface decreases, the reel's velocity reduces until it reaches a point where it stops rolling and begins to slide. Once this critical angle is surpassed, the forces acting on the reel cause it to reverse direction and roll towards the string. This phenomenon is explained by Newton's laws of motion, which dictate the relationship between forces and motion. Understanding this behavior requires analyzing the forces involved and their effects on the reel's movement.
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A string is wrapped around a reel. The reel is the set on a horizontal flat surface. This string is set perpendicularly to a surface and pulled. The reel starts to roll in the direction away from the string. However, as the angle between the reel string and the surface decreases, the velocity of the reel decreases, until it reaches an angle where it doesn't roll, but rather just slides. After the angle has been passed the reel starts rolling in the opposite direction, towards the string.

My question is, what causes this phenomenon? Why does the reel start moving in the opposite direction, and not just continue moving in the same direction?
 
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Welcome to PF;
It is a consequence of Newton's laws.
Try sketching out the situations and put the forces on.
 

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