The free body diagram of the forces acting on the child is shown in the image attached.
How to draw the free body diagram of the child?
The free body diagram of the forces acting on the child consists of the following;
Weight of the child acting downwards (W)
The normal force of the ground acting upwards on the child (N)
The perpendicular component of the child's weight (mg cosθ)
The parallel component of the child's weight (mg sinθ)
The kinetic friction opposing the motion of the child (Fs)
Thus, the free body diagram of the forces acting on the child is shown in the image attached.