A box of 20.0 kg is on a horizontal floor. We pull the box using a rope held at 30.0° above the horizontal. The coefficient of static friction between the box and the floor is 0.15. a) Draw the free body diagram of the situation. b) What tension must be applied in the rope to set the box in uniform rectilinear motion (constant velocity)? c) Calculate the normal force (reaction force from the ground). d) Deduce the coefficient of kinetic friction of the system if we consider that the box moves in uniform rectilinear motion at 1.6 m/s. e) If we decrease the pulling angle to 25° while maintaining the same tension in the rope, what will be the speed of the cart 2 seconds later? f) What would happen if we reset the rope to 30° after 2 seconds?