Question

A car moving at 5.73 m/s with a mass of 1,176 kg runs into a brick wall. If the car comesto rest over 19.9x10s during the collision, what is the force of the wall on the car?

Answer 1

Answer:

3.17 x 10^5 N

Explanation:

The impulse is defined as the change in momentum:

$I=m\Delta v$

which is related to the force applied over time t:

$I=Ft$

therefore,

$m\Delta v=Ft$

Now in our case, the momentum of the car goes from some value to zero in 19.9 x 10^-3 s; therefore,

t = 19.9 x 10^-3, m = 1176 kg and Δv = 5.73 - 0 = 5.73 m/s.

Putting the above values into the equation gives

$1176(5.73)=F(19.9\times10^{-3})$

dividing both sides by 19.9 x 10^-3 gives

$F=\frac{1176\cdot5.73}{19.9\times10^{-3}}$

which evaluates to give

$F=317,343\; N$$\boxed{F=3.17\times10^5N}$

which is our answer!