megz wrote:E= MC^2
A bullet has little mass, a wheel and tyre assembly would weigh much more and in the case of Henry Surtees you'll need much more than 3.5mm of Polycarbonate to dissipate all the energy of a wheel and tyre colliding with a canopy at 200+ kph I should think.
I think you're thinking of Force = Mass x Velocity squared
But you also need to consider that the area that the force is spread over also comes into play. A bullet has a tiny impact surface, and so exerts a lot of force through that tiny area. A tyre, or spring, would have a relatively much larger impact area and so the force would be dispersed.
If you want a real world example that you can try and home, take a thumb tack and first off push it into a piece of wood the right way round (sharp point towards the wood, wide flat head agint your thumb). Now try it the other way around with the sharp pointy bit against your thumb and the wide flat part against the wood...
This is why bullet proof glass has to be so thick - it is designed to resist the force being exerted on a tiny area. They also assume that there might be more than 1 bullet.
You wouldn't need to apply this to an F1 cockpit to deflect springs, tyres etc.
Otherwise supersonic fighter jets would have to have screens several inches thick to withstand bird-strikes....they don't, they have thinner screens designed to deflect the impact.