Matt Q said:
Jeesus dude I'm guessing you did lower grade science right?
Since F=ma and acceleration is a measurement of the CHANGE of the given relative speed of an object then a heavier object is actually HARDER to stop than a light object... also the heavier object will RESIST the deceleration more thereby putting more strain on the structure of the object during a crash scenario. The heavier car carries MORE energy than a lighter car and therefore has more energy to transfer to heat and noise during a crash...
Also you are using TOTALLY the wrong equation since the one above is a measure of the force REQUIRED for acceleration of an object.. and yes, heavier objects are HARDER to accelerate (or decelerate) but if 2 objects are moving at the same speed the heavier one will be carrying more Kinetic energy and it's KINETIC ENERGY which cause the kuk
The kinetic energy of an object is related to its momentum by the equation:
Ek = P2(Squared)
---
2M
where:
P is momentum
M is mass of the body
and Ek is Kinetic Energy
Your survival rate is obviously helped by all the safety gear which pushes up the weight (and therefore increases Kinetic energy), but it would still be safer in a light car with a very strong cage.... also.. a heavier car resists ALL changes in direction more.. IE turning. braking etc are all using force (f=ma) which is a resisting force (either brakes turning kinetic energy into heat through clamping force f or tyres using frictional force to change direction of travel, leaking off kinetic energy Ek as heat through the tyres)
Are you still with me??
EDIT - I recon Sankekur and I were typing at the same time - lol - he just has manners but I'm smarter
As always Matt, having an objective argument goes pear shaped rather quickly when you're involved... :slap:
Lower grade science actually sounds like fun. :thumbsup:
Lets take a head-on collision between an e46 M3 and an E90 M3 as an example.
Using the theory of conservation of momentum, the momentum prior to and following an accident is equal. The assumption is that the two vehicles collide and move together at a final velocity. This can be simplified to give the final velocity as a vector (given by 1). According to the difference in masses, the velocity will be in a set direction.
Using the equations of motion, the acceleration (or deceleration rather) can be found by comparing the initial velocities with the final one (equations 4 and 5).
As can be seen by the pic, the acceleration a1 is lower than that of a2. It's not by a large amount, but a1 is lower than a2. What has also been shown is the If the same calculation is done for a 5 ton truck and a 2 ton sedan, the difference is large. a1 = 13m/s^2 and a2 = 53 m/s^2.
Looking at kinetic energy shows there is a larger change in energy in a heavier vehicle moving at the same initial speed as a lighter vehicle. This is slightly misleading, because there are no considerations for the collision.
So a heavy vehicle will experience a lower deceleration due to it's larger mass.
Leading back to my first statement about Newtons Second Law, for a given applied force, the acceleration experienced will be,lower for a heavier vehicle. The lower an acceleration experienced by a human body, the higher the chance of survival.
Damn standard grade physics... :wave:
rick540 said:
This inertia debate is missing something.
Larger cars have proportionately larger crumple zones, I'm sure the manufacturers thought about this inertia thing beforehand.
Now a large car hitting a small car (heavyweight crumple zone Vs a lightweight crumple zone taking the energy stored and then dissipated into account)
In this scenario, the large car crumple zone will still be absorbing energy when the small car crumple zone has been "used up" and the large car will then begin transferring some of it's own kinnetic energy to the smaller car thereby fully fscking it up.
This is why one doesn't play chicken with 18 wheeler trucks, we all know what happens, the one with the significantly larger kinetic energy wins outright.
Maybe I'm talking utter S&^%t but I personally prefer driving a bigger car even with the performance loss
Rick, I do agree with you. The heavier vehicles will most likely have larger crumple zones...
