If the string connecting the puck to the center is cut, there will be no net force on the puck. (The force of gravity is offset by the turntable.) The puck will not accelerate or change direction, so it will move at a constant speed in the direction it was moving at the time the string was cut. How does this relate to the boy whirling a yo-yo given at the start of this Exploration sheet

Solution :

In the context, it is given that a boy is whirling a yo-yo in the counter clockwise direction above his head.

Similarly when a pink puck is floating above the circular table in uniform circular motion. Now when the string connecting the pink puck is cu at the center, no net force will be acting on the puck and it will not change its direction nor accelerate. But the puck will move at a constant speed.

Both the scenarios are same . But incase of the boy playing with the yo-yo, we consider the gravity force.

an obstruction