A box of mass 3.06 kg slides down a rough vertical wall. The gravitational force on the box is 30 N . When the box reaches a speed of 2.5 m/s , you start pushing on one edge of the box at a 45∘ angle (use degrees in your calculations throughout this problem) with a constant force of magnitude Fp = 23 N , as shown in (Figure 1) . There is now a frictional force between the box and the wall of magnitude 13 N . How fast is the box sliding 2.6 s after you started pushing on it?

I've already found the box's speed vf at 2.6 s after you first started pushing on it. which was 3.1 m/s

But now I'm being asked the following question And I need to know how to set it up and solve it showing all the steps. I've tried many ways put I'm just missing something

Assuming that the angle at which you push on the edge of the box is again 45∘ , with what magnitude of force Fp should you push if the box were to slide down the wall at a constant velocity? Note that, in general, the magnitude of the friction force will change if you change the magnitude of the pushing force. Thus, for this part, assume that the magnitude of the friction force is f=0.566Fp

Thanks