AP Physics C: Mechanics Flashcards: Forces and Free-Body Diagrams
Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026
Review key ideas with interactive flashcards. This set includes 11 cards to help you master important concepts.
What specific forces should be included when drawing a free-body diagram for a system?
The diagram should only include forces exerted on the object or system by its external environment.
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What specific forces should be included when drawing a free-body diagram for a system?
The diagram should only include forces exerted on the object or system by its external environment.
To simplify the equations of motion for a satellite orbiting Earth, how might you orient one axis of your coordinate system?
You would align one axis with the direction of acceleration, which points from the satellite directly toward the center of the Earth.
Can a person sitting in a small boat make it move by pushing on the boat's mast? Explain why or why not.
No, because the person and boat are part of the same system. A system cannot exert a net force on itself to cause acceleration.
Define 'force' based on its fundamental nature and properties.
A force is a vector quantity that describes an interaction between two objects or systems.
A car is parked on a hill. Why is the force the car's tires exert on the road not included in the car's free-body diagram?
A free-body diagram only shows forces exerted *on* the object (the car) by the environment, not forces the object exerts *on* the environment (the road).
What type of quantities are forces, and what does this imply?
Forces are vector quantities, which means they possess both a magnitude (strength) and a direction.
What is a fundamental principle regarding the forces an object or system can exert on itself?
An object or system cannot exert a net force on itself.
What is the origin of any force acting upon an object?
A force is always the result of an interaction between two separate objects or systems.
How does describing a force as an 'interaction' clarify its nature?
It emphasizes that a force is a mutual push or pull between two different objects, not a property possessed by a single object in isolation.
What is a free-body diagram?
A free-body diagram is a representation that shows each of the forces exerted on a single object or system by its environment.
What is the most effective way to orient a coordinate system when analyzing forces on an accelerating object?
To simplify the algebraic representation, one axis of the coordinate system should be aligned parallel to the direction of the object's acceleration.