Answer:
W = -37.5 J
Explanation:
Work And Energy
The work-energy theorem indicates that the work done by forces acting on an object equals the change in the kinetic energy experienced by the object. If the kinetic energy is lost during the experience, the work is negative.
[tex]W=\Delta K[/tex]
[tex]\displaystyle K_1=\frac{mv_1^2}{2}[/tex]
[tex]\displaystyle K_2=\frac{mv_2^2}{2}[/tex]
[tex]\displaystyle \Delta K=\frac{mv_2^2}{2}-\frac{mv_1^2}{2}[/tex]
We have: [tex]v_1=5\ m/s, v_2=0, m= 3\ kg[/tex]
[tex]\displaystyle \Delta K=\frac{(3)0^2}{2}-\frac{(3)5^2}{2}[/tex]
[tex]\displaystyle \Delta K=-\frac{75}{2}=-37.5\ J[/tex]
The work done by the friction force is
[tex]W=-37.5\ J[/tex]
