Question

The use of air bags in cars reduces the force of impact by a factor of 110.(The resulting force is only as great.) What can be said about how the airbag changed the duration of the collision?

Answer 1

The variation of momentum (= the impulse) of the car during the impact is
$\Delta p = F \Delta t$
$\Delta p$ does not change whether the car has an airbag or not, because 
$\Delta p = m\Delta v$
and 1) the mass of the car is always the same 2) the change in velocity of the car is always the same,

so if $\Delta p$ is constant and F is reduced by a factor 110, then $\Delta t$ (the duration of the collision) must be increased by a factor 110 with the airbag.

Answer 2

the answer is C. it increases by a factor of 110, i got 100 on the test