"Science: Why Shoelace Knot Failure"

Question

by Nsikan Akpan

To break down the physics of the phenomena, the researchers attached a small device to the free end of the laces that measured acceleration, and then Gregg went for a walk or a jog. This acceleration creates inertia, which is the tendency for an object to keep moving once it is in motion.

“We were surprised that the accelerations were so high. They’re like 7 g [units of acceleration] ,” O’Reilly said. “By way of comparison, the highest g on a roller coaster are 6.3. Your foot is experiencing these really high g-forces as you’re running all the time. It’s a biomechanical miracle that all of that impact is absorbed through your body and spine.”

The knot itself is under pressure too. The videos showed as the shoelaces bounce up and down with each footfall, the main knot begins to deform. Once the knot opens sufficiently, then the free end of the lace, which is being tugged by inertia, begins to slip out.

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Question
Use the passage from “The Science Behind Why Your Shoelace Knot Is Doomed to Fail” by Nsikan Akpan to answer the question.

Connection: The g-forces put pressure on the knots in the same way they put pressure on the body and spine.

Which pieces of evidence support the connection? Select the two correct answers.

(1 point)
Responses

“To break down the physics of the phenomena, the researchers attached a small device to the free end of the laces that measured acceleration, and then Gregg went for a walk or a jog.”
“To break down the physics of the phenomena, the researchers attached a small device to the free end of the laces that measured acceleration, and then Gregg went for a walk or a jog.”

“We were surprised that the accelerations were so high.”
“We were surprised that the accelerations were so high.”

“This acceleration creates inertia, which is the tendency for an object to keep moving once it is in motion.”
“This acceleration creates inertia, which is the tendency for an object to keep moving once it is in motion.”

“The videos showed as the shoelaces bounce up and down with each footfall, the main knot begins to deform.”
“The videos showed as the shoelaces bounce up and down with each footfall, the main knot begins to deform.”

“Your foot is experiencing these really high g-forces as you’re running all the time.”

Answer 1

The two pieces of evidence that support the connection between the g-forces putting pressure on the knots and their effect on the body and spine are:

1. “Your foot is experiencing these really high g-forces as you’re running all the time.”
2. “The videos showed as the shoelaces bounce up and down with each footfall, the main knot begins to deform.”

These statements illustrate how the high g-forces experienced by the foot during running contribute to the deformation of the shoelace knot, paralleling the pressure exerted on the body and spine during motion.