What is the net force and kinetic energy of an 800g part hitting at 170mph?

AI Thread Summary
Felipe Massa suffered a severe head and eye injury during the Grand Prix of Hungary when an 800 g coil suspension spring struck his helmet at approximately 170 mph. The impact force is complex to calculate, as it depends on the contact time between the spring and Massa, but using basic physics, the kinetic energy of the spring at that speed is estimated to be around 2.3 kJ. The helmet's design helps distribute the force over a larger area, reducing tissue damage compared to a bullet, but the energy absorbed by the brain and neck muscles remains significant. The discussion highlights the challenges in calculating impact forces in high-speed racing incidents. Overall, the incident underscores the dangers of motorsport and the physics involved in such accidents.
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This past weekend - Sunday, July 26th to be precise - Ferrari Formula 1 driver Felipe Massa suffered a HORRIBLE head / eye injury in the Grand Prix of Hungary as a result of an object striking his helmet and visor after having been "thrown" (disconnected) from another racing car ahead - an 800 g coil suspension spring. He was traveling (according to telemetry) approximately 170 mph at the moment of impact.

What was the net force of impact upon him - in "American" units?

Is it a simple f = m x a equation? If so, 800 g = 1.764 pounds of "mass" and his speed (acceleration or velocity) - 170 mph - equals almost 250 feet / second. Where do I drop out the "second" and call this about 440 pounds / feet of energy striking him?

Or is there a more correct formula?

(Trying to convince those in a non-technical office environment as to the laws of physics acting upon us ...)

Thank you.
 
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Not quite, to know the force you would have to know how long the spring was in contact with the driver.
Assuming the spring was stationary when he hit it, it will be accelerated upto the speed of his car (170mph) the quicker this happens the more force involved. It's very difficult to calculate this - you are probably better thinking in terms of the kinetic energy.
 
As far as "contact time", this could best be described as a bullet - a rather s-l-o-w, *reverse motion* bullet - that is, the object did not penetrate the human form in the same manner. It (the impact moment) could be called "instantaneous" as in "a glancing blow".

By "reverse motion", I'm being cute: Massa and car were in projectile(s) motion; the semi-stationary object (the 800 g spring) the target. In fact, suspend a bullet in mid-air for a split-second and force a target into it; that's a more proper scenario.

Television replays appeared to show the spring in motion (?) TOWARDS the driver that was hit - or perhaps almost suspended in air as if rebounding (from a bounce on the tarmac racing surface) due to being thrown (or projected) after the part became disconnected. The illusion of being propelled backwards cannot be discounted as it was possibly given momentum from coming in contact with a (rapidly rotating) rear tire of the vehicle that lost it.

The spring WAS freely airborne when it came into contact with Massa's visor and the impact clearly forced his entire helmeted head backwards - violently and abruptly - onto his racing car's head-rest.

Again, using the simple f = m X a equation - and your excellent retort, "mgb_phys", thank you! - I feel Felipe Massa was struck by AT LEAST 440 pounds / feet of energy - a description (pounds / feet) often used to illustrate the energy in a bullet ... because that, essentially, was what the projectile was that impacted him. It simply was not "fired" from a gun.

Kind regards,
 
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A typical modern military bullet weighs around 4g and has a muzzle velocity of around 900m/s so a kinetic energy of 1.7 KJ
A 800g part hitting you at 170mph (76m/s) has a KE of around 2.3KJ.

The helmet spreads the force out over a larger area so does less tissue damage than the bullet but the energy ultimately absorbed by the brain and neck muscles is similar.
 
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