The study of forces and their effect on motion, explaining why objects move as they do.

The force pulling an object down due to gravity, calculated as $W = mg$, where g is the acceleration due to gravity.

The force exerted by a surface on an object, always perpendicular to the surface.

The pulling force exerted by a string, rope, cable, or similar object on another object.

A force that opposes motion between surfaces in contact.

A defined collection of objects being studied, crucial for determining internal and external forces.

The region around a massive object where other massive objects experience a gravitational force.

The tendency of an object to resist changes in its state of motion.

The object accelerates in the direction of the net force, as described by Newton's Second Law ($F = ma$).

The object's velocity remains constant (including zero), according to Newton's First Law.

The acceleration of the object decreases, as described by Newton's Second Law ($a = F/m$).

1. Draw the object as a point or simple shape. 2. Draw arrows (vectors) to represent each force, with the tail on the object. 3. Label each force.

Analyze the whole system or individual masses by applying Newton's Second Law to each mass and considering the tension in the string.