| Pairs of forces that occur when two objects interact. They are always of the same type, have the same size, and act in opposite directions. | Action-Reaction Forces |
| What are action-reaction forces? | Pairs of forces that occur when two objects interact, always of the same type, having the same size, and acting in opposite directions. |
| Forces that result from the physical interaction or touching of two objects. | Contact Forces |
| What are contact forces? | Forces that result from the physical interaction or touching of two objects. |
| Forces that act between objects without any physical interaction or direct contact. | Non-contact Forces |
| What are non-contact forces? | Forces that act between objects without any physical interaction or direct contact. |
| The equal and opposite forces in action-reaction force pairs. | Force Pairs |
| What is the defining characteristic of force pairs in action-reaction forces? | They are equal and opposite. |
| A quantity that has both magnitude (size) and direction, represented graphically with an arrow. | Vector |
| How are forces represented graphically? | Forces are represented as vectors with arrows indicating their size and direction. |
| The force created when one object pushes against another, always acting at right angles to the surface between the two objects. | Normal Contact Force |
| What is the normal contact force? | The force created when one object pushes against another, always acting at right angles to the surface between the two objects. |
| The force that acts to resist the motion or sliding of two objects past each other. | Friction |
| What is friction? | The force that acts to resist the motion or sliding of two objects past each other. |
| The frictional contact force that opposes the motion of an object as it moves through the air. | Air Resistance |
| What is air resistance? | The frictional force that opposes the motion of an object as it moves through the air. |
| The frictional contact force that opposes the motion of an object as it moves through water. | Water Resistance |
| What is water resistance? | The frictional force that opposes the motion of an object as it moves through water. |
| The non-contact force of attraction between two masses, such as the force between the Earth and an object. | Gravitational Force |
| What is gravitational force? | The force of attraction between two masses, such as the force between the Earth and an object. |
| The non-contact force between electrically charged objects, which can be attractive (opposite charges) or repulsive (like charges). | Electrostatic Force |
| What is electrostatic force? | The force between electrically charged objects, which can be attractive (opposite charges) or repulsive (like charges). |
| The non-contact force between magnets or magnetic objects. | Magnetic Force |
| What is magnetic force? | The force between magnets or magnetic objects. |
| The area around an object where it can exert a non-contact force on other objects. | Force Field |
| What is a force field? | The area around an object where it can exert a non-contact force on other objects. |
| The process of applying a substance (usually oil) to reduce friction between moving parts in a mechanical system. | Lubrication |
| What is lubrication? | Lubrication is the process of applying a substance (usually oil) to reduce friction between moving parts in a mechanical system. |
| Energy that is transferred to less useful forms, often in the form of heat. | Dissipated Energy |
| What is dissipated energy? | Dissipated energy is energy that is transferred to less useful forms, often in the form of heat. |
| Energy that is not used for a useful purpose in a system. | Wasted Energy |
| What is wasted energy? | Wasted energy is energy that is not used for a useful purpose in a system. |
| The ratio of useful energy output to the total energy input in a system. | Energy Efficiency |
| What is energy efficiency? | Energy efficiency is the ratio of useful energy output to the total energy input in a system. |
