AP Physics C: Mechanics Flashcards: Circular Motion
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.
What is the magnitude of centripetal acceleration for an object in a circular path?
It is the ratio of the object's tangential speed squared to the radius of the circular path.
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What is the magnitude of centripetal acceleration for an object in a circular path?
It is the ratio of the object's tangential speed squared to the radius of the circular path.
How is the motion of an object traveling in a circular path described?
The object is constantly accelerating towards the center of the circle, even if its tangential speed is constant.
What is the equation for the magnitude of centripetal acceleration ($a_c$)?
The equation is $a_{c}=\frac{v^{2}}{r}$, where 'v' is the tangential speed and 'r' is the radius of the path.
According to Kepler's third law for circular orbits, what determines the relationship between the orbital period and radius?
The period and radius of a circular orbit are related to the mass of the central body being orbited.
If a car doubles its speed while rounding a curve of a constant radius, how does its centripetal acceleration change?
Since $a_c$ is proportional to $v^2$, doubling the speed will cause the centripetal acceleration to become four times greater.
What two variables of an object's circular motion are used to calculate its centripetal acceleration?
The object's tangential speed (v) and the radius (r) of its circular path are used.
What equation, derived from Kepler's third law, relates an orbit's period (T) and radius (R) to the central body's mass (M)?
The equation is $T^{2}=\frac{4\pi^{2}}{GM}R^{3}$.
Two satellites orbit the same planet. If Satellite A has a larger orbital radius than Satellite B, which satellite has a longer period?
Satellite A will have a longer period because the orbital period squared is directly proportional to the orbital radius cubed ($T^2 \propto R^3$).
If the radius of a circular orbit is increased, what happens to the orbital period, assuming the central mass is constant?
According to $T^{2} \propto R^{3}$, increasing the orbital radius (R) will also increase the orbital period (T).
An object moves in a circular path with a constant speed. If the radius of the path is decreased while the speed stays the same, what happens to the centripetal acceleration?
The centripetal acceleration will increase because it is inversely proportional to the radius ($a_c = v^2/r$).