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question 7
air bags are used by stunt people when they fall off buildings to reduce the ___ that occurs during the collision.
change in momentum
impulse
force
change in velocity

Explanation:

According to the impulse - momentum theorem \(J=\Delta p = F\Delta t\). When a stunt person falls, the change in momentum \(\Delta p\) (which is related to the initial and final velocities, \(p = mv\)) is fixed (assuming the same initial velocity before hitting the air - bag and the same final velocity after coming to rest relative to the air - bag). The impulse \(J=\Delta p\) is also fixed. However, the air - bag increases the time of collision \(\Delta t\). From \(F=\frac{\Delta p}{\Delta t}\), when \(\Delta p\) is constant and \(\Delta t\) increases, the force \(F\) acting on the stunt person decreases.

Answer:

force