physics
posted by bryan .
the initial velocity of a 4 kg box is 11 m/s, due west. after the box slides 4 m horizontally its speed is 1.5 m/s. determine the magnitude and the direction of the non conservative force acting on the box as it slides.

KE2KE1=W(fr) =F•s
mv₂²/2  mv₁²/2 = F•s
Solve for F