Answer to Question #135424 in Mechanics | Relativity for Sama

Question

An object of mass m moves with an acceleration a down a rough incline. Which of the following should NOT appear in a free-body diagram of the object and WHY? (a) the gravitational force exerted by the planet (b) ma in the direction of motion (c) the normal force exerted by the incline (d) the friction force exerted by the incline

Answer 1

A) Since in the diagram of the free body of an object, only the forces acting on the body must be specified.

B) Since this is just a projection of $\vec g \times m$ on the axis along the slope.