1. As shown in the figure, an object placed on the horizontal ground is acted upon by a horizontal thrust F with a constant direction. The relationship between the size of F and time t, and the relationship between the object's moving speed v and time t are as shown in the figure. It can be seen from the image that when t=1s, the object is in ______ state; when t=3s, the friction force on the object is ______N; when t=5s, the friction force on the object is ______N; if the 2s arrives The distance moved in the 4th s is 4m, then the average speed from the 2nd to the 6th s is ______m/s.
