Physic question,driver inside 2 very small car collison suffer more injury or 2 very large car?

It sounds as though you are asking about these scenarios:

1) two of the smallest hatchback cars collide

v.

2) two of the largest pickup trucks collide

??

If you are wondering about comparing these collisions at the same SPEEDS...then there are some things we can say.

With

A) the small cars both of the same make & model year and equipped identically to each other, and

the large trucks both of the same make & model year and equipped identically to each other,

AND

B) a collision type which would look the same from each vehicle's perspective (i.e., a head-on collision, squarely hit)

AND

C) at the SAME speed for EVERY vehicle,

then

we expect both sets of passengers in the same group (small car or big truck) to sustain substantially similar injuries, etc., by the symmetry of the set-up.


However, crashes are mostly about the behavior of the vehicles under inelastic collisions (where the energy of motion is NOT conserved)--so that much of the energy of motion has to be absorbed by the vehicles (this is why vehicles are now designed with "crumple zones", areas designed to absorb energy via being deformed).

The real question is what is the relative energy to be dissipated in the two crashes.

Since we are assuming straight-line travel,

E_j = m__j * (v_j^2)/2

where

E_j is the kinetic energy of the jth vehicle,

m_j is its mass, and

v_j is its speed.

For your given problem, I'll wager that

m_{smallest hatchback} < m_{large pickup truck}

For a 2024 Mitsubishi Mirage ES CVT,
the weight (not mass) is

2084#

The 2005 International CXT, the largest standard production pickup ever made, has a weight of

14,500#


So the ratio of the energies of the a SINGLE CXT to a SINGLE Mirage is

r ≡ E_{CXT}/E_{Mirage}
= m_{CXT}/m_{Mirage}
= w_{CXT}/w_{Mirage} (ratio of weights)

or

r = (14,500 / 2084)

for 6.96 x the energy!

It also has lot more mass, but I'd rather take my chances with the vehicle having the LOWER mass and LESS energy to have to absorb.

The forces involved are dependant on mass as well as velocity so increase with both.

The occupants' survival the collision depends much more on how well the vehicle withstands the impact, and on how well the occupants are protected by vehicle design and on precautions like wearing the seat-belts.

In a frontal collision an unrestrained occupant (not wearing a seat-belt) will be propelled forwards with the momentum from his or her own mass and the original speed just at point of collision, and irrespective of vehicle type. (Momentum =mass X velocity.)

If the driver is unrestrained and suffers a head-on crash at speed he or she will smash into the steering-wheel and windscreen with just the same force whether driving a 40-tonne lorry or a small saloon car.

Modern cars are designed to absorb a lot of the force by crumpling in such a way that it reduces the risk of crushing the occupants by the engine being forced back into the interior; and of course are fitted with protective devices like air-bags, seat-belts and glass made to shatter rather than break into shards. They are also lighter than their equivalents built, say, fifty years ago, so the overall forces are lower.

Issues that impact it: car design, safety features installed in cars, direction of impact. On the face of it, passengers in a smaller car will be at a higher risk.

I'm not sure I understand your question, but if two cars collide head on, you'll have a much better chance of surviving the accident if you're in a vehicle that is the larger of the two, and if you're on a motorcycle and end up colliding with a truck, you're kaput, finished.

2 large