Ablock of mass m slides down a frictionless plane inclined at an angle θ with the horizontal. the gravitational force is directed *

perpendicular to the plane

Explanation:

The gravitational force is the force pulling down objects down and is usually directed downwards. As the mass is on the plane the force of gravity acts vertically downwards on the mass. see attached for graphical illustration. The mass slides down the plane at an angle while the gravitational force is a perpendicular force parallel the plane. It acts downwards facing opposite the angle.

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