Question

1. during a car collision test, two crash test dummies are given a velocity of 27 m/s, and then brought to a stop.

dummy jimmy is stopped with a cement wall, while dummy casey is stopped with an airbag. both dummies have
the same mass.
which dummy has a higher impulse applied to him?
dummy jimmy
they have the same impulse
they have no impulse
dummy casey

Explanation:

Step1: Recall the impulse - momentum theorem

The impulse - momentum theorem states that \(J=\Delta p = m(v - u)\). Both dummies have the same initial velocity \(u = 27m/s\) and the same final velocity \(v = 0m/s\), and assume they have the same mass \(m\) (since they are crash - test dummies, we can assume identical mass for the purpose of comparing impulse in this context).

Step2: Calculate the impulse for each dummy

For Dummy Jimmy: \(J_{Jimmy}=m(0 - 27)=- 27m\). For Dummy Casey: \(J_{Casey}=m(0 - 27)=-27m\). The magnitude of the impulse \(|J|\) is what we consider for comparison. The magnitude \(|J| = 27m\) for both dummies.

Answer:

They have the same impulse