A uniform ladder of length 10 feet and weighing 20 pounds leans against a vertical wall while making an angle of 53 degrees between the foot of the ladder and the floor of the room. Assume that a person weighing 160 pounds is three-fifths (measured from the foot of the ladder) the way up (along) the ladder. Assume the vertical wall is smooth (no friction). Find the size of the normal force at the foot of the ladder.