Question

Highway safety engineers want to design roadside barriers that will crumple

Answer 1

Answer:

$0.84\:\text{s}$

Explanation:

The impulse-momentum theorem states that the impulse on an object ($F\Delta t$) is equal to the change in momentum of that object ($\Delta p$).

Set up the following equation:

$F\Delta t=\Delta p$

Solving for change in momentum:

The momentum of an object is equal to $p=mv$, where $m$ is the mass of the object and $v$ is the velocity of the object. Since the person's final velocity will be zero, their final momentum will also be zero. Therefore, the person's change in momentum is $68\cdot 27-0=1836\:\text{kgm/s}$.

Solving for time:

$2180\cdot\Delta t = 1836,\\\Delta t =\frac{1836}{2180},\\\Delta t =\boxed{0.84\:\text{s}}$

Answer 2

Answer:

If the engineers know that the

If the engineers know that themaximum force that a person can safely withstand is 2180 N, approximately, 0.84 second is required to crumple the barrier to safely slow the person

is required to crumple the barrier to safely slow the personwith this force.