A chair of mass $13.5 \mathrm{~kg}$ is sitting on the horizontal floor; the floor is not frictionless. You push on the chair with a force $F=35.0 \mathrm{~N}$ that is directed at an angle of $38.0^{\circ}$ below the horizontal, and the chair slides along the floor. (a) Draw a clearly labeled free-body diagram for the chair. (b) Use your diagram and Newton's laws to calculate the normal force that the floor exerts on the chair.