AP Physics C: Mechanics Flashcards: Motion in Two or Three Dimensions
Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026
Review key ideas with interactive flashcards. This set includes 10 cards to help you master important concepts.
A cannonball is fired horizontally from a cliff. How does its initial horizontal velocity affect its vertical acceleration?
The initial horizontal velocity has no effect on its vertical acceleration. The cannonball's vertical motion is only affected by the constant, nonzero acceleration due to gravity.
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A cannonball is fired horizontally from a cliff. How does its initial horizontal velocity affect its vertical acceleration?
The initial horizontal velocity has no effect on its vertical acceleration. The cannonball's vertical motion is only affected by the constant, nonzero acceleration due to gravity.
What is the fundamental strategy for solving problems involving motion in two or three dimensions?
The fundamental strategy is to separate the motion into perpendicular components. This allows the motion in each dimension to be analyzed independently using 1D kinematics.
What are the specific acceleration conditions for projectile motion?
For projectile motion, the acceleration in one dimension is zero, while the acceleration in the perpendicular dimension is constant and not zero.
How can the complex motion of an object in two or three dimensions be simplified for analysis?
Motion in two or three dimensions can be simplified by separating it into perpendicular components, allowing each component to be analyzed using one-dimensional kinematic relationships.
Term: Component-wise analysis of motion
This is the method of analyzing 2D or 3D motion by breaking it down into independent, perpendicular components and applying one-dimensional kinematic relationships to each component.
A swimmer crosses a river with a strong current. How can you analyze her motion relative to the riverbank?
You can analyze her motion by separating it into two components: her velocity across the river and the river's current velocity downstream. These perpendicular motions are independent of each other.
An object is dropped, and another is thrown horizontally from the same height at the same time. Which principle explains why they hit the ground simultaneously?
The principle that motion in one dimension may be changed without affecting motion in a perpendicular dimension explains this. The horizontal motion does not alter the independent vertical motion due to gravity.
What is the principle of independence of motion in perpendicular dimensions?
This principle states that motion in one dimension can be changed without causing a change to the motion in a perpendicular dimension.
What is projectile motion?
Projectile motion is a special case of two-dimensional motion characterized by zero acceleration in one dimension and a constant, nonzero acceleration in the second, perpendicular dimension.
Why is it advantageous to use one-dimensional kinematic relationships for analyzing 2D motion?
It is advantageous because after separating the 2D motion into components, the well-established and simpler 1D kinematic equations can be applied to each dimension independently.