Neeraj Chopra: A look at the physics that causes a javelin to fly past the 90-meter “gold standard” distance, where a healthy rivalry between Arshad Nadeem of Pakistan and Neeraj Chopra of India is expected to intensify in future events.
Arshad Nadeem of Pakistan won his nation’s first javelin throw gold on Sunday with a mark of 90.18 metres, a Commonwealth Games record. Nadeem has broken the 90-meter barrier that Neeraj Chopra of India has yet to do. Chopra’s personal best is 89.94m, but he was injured and missed the CWG competition.
Chopra won a gold medal in the javelin on August 7 of last year at the Tokyo Olympics, giving India its first-ever athletics victory. We examine the physics that causes a javelin to fly past the 90 m “gold standard” distance in light of the healthy rivalry between the two stars that is expected to intensify in future javelin events.
Although high school physics suggests that a projectile should be launched at a 45-degree angle for maximum range, Dr. Arnab Bhattacharya, professor at the Department of Condensed Matter Physics & Materials Science, Tata Institute of Fundamental Research, Mumbai, tweeted last year that this is only true when the launch and the target are at the same height.
In the javelin, the launch takes place 2 metres above the ground, the target is on the ground, and various aerodynamics-related factors are at play. As a result, the ideal angle is 36 degrees.
Design is crucial.
The crucial idea is that the centre of gravity must be four centimetres (4 cm) in front of the centre of pressure. A modern javelin’s design already includes this. The javelin’s weight distribution and shape put the centre of gravity before the centre of pressure. When throwing, the player keeps it close to their centre of gravity, according to additional information provided by Prof. Bhattacharya in an email to The Indian Express.
At all moments while in flight, the javelin must sink, and the tip must touch the ground first.
The initial run-up, angular momentum, and release dynamics are also things that affect the trajectory and final distance thrown (speed, height, angle).
Elite throwers are thought to release the javelin at a speed of 28–30 m/s (100 km/h), with an average maximum run-up speed of 5–6 m/s (20 km/h).
Prof. Bhattacharya continues by mentioning the importance of the angle of attack, wind speed and direction, air temperature, and density.
Looking just at the physics of the throw, lift from the air is a significant issue for the javelin. Lower air temperatures result in slightly denser air, which provides a tiny boost in lift and allows for a slight increase in distance travelled. These effects will be minimal, but keep in mind that at the Olympics you can lose a medal or set a record by only a few millimetres, “he said.
The International Association of Athletics Federations sets rules for the javelin’s size, shape, minimum weight, centre of gravity, surface quality (no rough paint, dimples, etc.), and allowed throwing styles.
He stated that the javelin throw was a unique instance in which the IAAF intervened to amend the rules in order to shorten throw distances. This was because improvements (based on physics!) like hollow, designer cross-section, and surface texture made javelins more aerodynamic.
When asked if there were any additional physics-based adjustments that could be made, he responded that the IAAF had taken care to avoid “high-tech gimmicks” that could improve performance because they “would only be available to people who could afford to put in the resources to do all kinds of aerodynamic simulations and make “better” javelins.”
“I’d really want to see if someone can devise a new throwing technique that helps the javelin travel farther.” Naturally, it would be simpler for well-resourced participants to experiment with alternative throwing patterns and discover what could work better in today’s reality given that you have access to sophisticated computation and all kinds of sensors, while still adhering to the existing rules, he continued.