A car with a mass of 1180 kilograms is being driven at 18.2 meters per second when it runs into a tree. If the front of the car is pushed in 41.1 centimeters, what is the magnitude of the force exerted on the car? Include units in your answer. Answer must be in 3 significant digits.

Respuesta :

We know that the work is related to the kinetic energy by the work energy theorem:

[tex]W=K_f-K_i[/tex]

In this case the final velocity of the car is 0 m/s; with this in mind and plugging the values given for the initial velocty we have:

[tex]\begin{gathered} W=\frac{1}{2}(1180)(0)^2-\frac{1}{2}(1180)(18.2)^2 \\ W=-195431.6 \end{gathered}[/tex]

Now, we know that the work is given by:

[tex]W=Fd[/tex]

plugging the distance and the work done we have:

[tex]\begin{gathered} -195431.6=0.411F \\ F=-\frac{195231.6}{0.411} \\ F=-4.76\times10^5 \end{gathered}[/tex]

Since we need the magnitude we drop the sign, therefore the magnitude of the force is:

[tex]F=4.76\times10^5\text{ N}[/tex]