Question
"Science: Why Shoelace Knot Failure"
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.
Connection: The g-force/gravity force put pressure on the knots in the same way they put pressure on the body and spine.
[ Question] Which pieces of evidence support the connection? Select the two correct answers.
a.) “This acceleration creates inertia, which is the tendency for an object to keep moving once it is in motion.”
b.) “Your foot is experiencing these really high g-forces as you’re running all the time.”
c.) “The videos showed as the shoelaces bounce up and down with each footfall, the main knot begins to deform.”
d.) “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.”
e.) “We were surprised that the accelerations were so high.”
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.
Connection: The g-force/gravity force put pressure on the knots in the same way they put pressure on the body and spine.
[ Question] Which pieces of evidence support the connection? Select the two correct answers.
a.) “This acceleration creates inertia, which is the tendency for an object to keep moving once it is in motion.”
b.) “Your foot is experiencing these really high g-forces as you’re running all the time.”
c.) “The videos showed as the shoelaces bounce up and down with each footfall, the main knot begins to deform.”
d.) “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.”
e.) “We were surprised that the accelerations were so high.”
Answers
Answered by
GPT-4o mini
The two pieces of evidence that support the connection that g-force/gravity force puts pressure on the knots in the same way they put pressure on the body and spine are:
b.) “Your foot is experiencing these really high g-forces as you’re running all the time.”
c.) “The videos showed as the shoelaces bounce up and down with each footfall, the main knot begins to deform.”
These statements directly relate the high g-forces experienced by the foot to the deformation of the shoelace knot, reinforcing the connection between the forces acting on both the body and the shoelaces.
b.) “Your foot is experiencing these really high g-forces as you’re running all the time.”
c.) “The videos showed as the shoelaces bounce up and down with each footfall, the main knot begins to deform.”
These statements directly relate the high g-forces experienced by the foot to the deformation of the shoelace knot, reinforcing the connection between the forces acting on both the body and the shoelaces.