Power is knowledge?
A hypothetical exam question from 2014 regarding a helicopter and a rope scenario went viral as no one could agree on one right answer. To put everyone at ease, educational science YouTuber Derek Muller who runs the channel Veritasium, decided to end the debate once and for all by using the variables mentioned in the question, yes a helicopter and a rope. Anything in the name of science?
Muller rented a helicopter and turned the hypothetical question into a real scenario (Thank God for sponsorship deals). In the video, Muller starts by reading the question from the 2014 qualifying exam for the U.S Physics Team which states “”A helicopter is flying horizontally at a constant speed. A perfectly flexible uniform cable is suspended beneath the helicopter. Air friction on the cable is not negligible. Which of the following diagrams best shows the shape of the cable as the helicopter flies through the air to the right?” The question is followed by five multiple-choice answers which Muller also asked his audience before solving the question in real time.
Most of the people chose C as the right answer so they were in for a shock when E was found to be the correct answer. According to the solution section posted on the American Association of Physics Teachers’ (AAPT) website, “since there is air friction on the cable, then there must be a horizontal component to the force where the cable attaches to the helicopter.” The exam writer also states that “this question generated a great deal of controversy” and that “at least two test-takers challenged the answer.”
As Muller points out in the video, there are two external forces acting on the rope i.e gravity and air resistance. “When flying along at constant speeds, these forces must be perfectly balanced by the tension in the rope,” says Muller. To demonstrate the scenario, he makes use of a battle rope used in gyms. He also uses a 9kg kettlebell attached to the rope and a parachute as well because it’s not everyday you get to rent a helicopter for “research purposes”.