Question

part 1 of 2
a book is at rest on an incline as shown below. a hand, in contact with the top of the book, produces a constant force f_hand vertically downward.
the following figures show several attempts at drawing free - body diagrams for the book. which figure has the correct directions for each force? the magnitudes of the forces are not necessarily drawn to scale.

Explanation:

Step1: Identify forces acting on book

The forces are gravitational force $F_g$ (down - ward), hand - applied force $F_{hand}$ (down - ward), normal force $F_N$ (perpendicular to the incline), and frictional force $F_f$ (opposite to the tendency of motion).

Step2: Analyze direction of each force

Gravitational force and hand - applied force act vertically downward. The normal force is perpendicular to the surface of the incline. The frictional force acts up the incline to oppose the downward - sliding tendency of the book.

Answer:

The correct free - body diagram should have $F_g$ and $F_{hand}$ acting vertically downward, $F_N$ perpendicular to the incline, and $F_f$ up the incline. Among the given diagrams, the one with these correct directions for the forces is the answer (without seeing the specific correct diagram among the 5 options, we can't give an exact option number, but the correct one follows the above - described force directions).