Truck Collision


In a head-on collision:
Which truck will experience the greatest force?
Which truck will experience the greatest impulse?
Which truck will experience the greatest change in momentum?
Which truck will experience the greatest change in velocity?
Which truck will experience the greatest acceleration?
Which truck would you rather be in during the collision?

Discussion of the questions

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Truck Collision

Comparison of the collision variables for the two trucks:

In a head-on collision:

Newton's third law dictates that the forces on the trucks are equal but opposite in direction.

Impulse is force multiplied by time, and time of contact is the same for both, so the impulse is the same in magnitude for the two trucks. Change in momentum is equal to impulse, so changes in momenta are equal. With equal change in momentum and smaller mass, the change in velocity is larger for the smaller truck. Since acceleration is change in velocity over change in time, the acceleration is greater for the smaller truck.

Ride in the bigger truck! There are good physical reasons!


Collision questions

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Collision concepts
 
HyperPhysics***** Mechanics ***** Newton's laws R Nave
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Truck Collision


In a head-on collision the forces on the two vehicles are constrained to be the same by Newton's third law. But from both Newton's second law and the work-energy principle it becomes evident that it is safer to be in the bigger truck.

Even though the forces are equal in magnitude on the two trucks, the smaller truck experiences the greater acceleration.

The change in velocity of the driver will be the same as the truck in which he/she is riding. A greater change in velocity implies a greater change in kinetic energy and therefore more work done on the driver.

Collision questions Relation of fatalities to vehicle mass
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Collision concepts
 
HyperPhysics***** Mechanics ***** Newton's laws R Nave
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