AP Physics 1: Algebra-Based 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 16 cards to help you master important concepts.
A planet is discovered orbiting a star that is twice as massive as our Sun, but at the same orbital radius as Earth. How would the planet's orbital period compare to Earth's?
According to $T^2 = \frac{4\pi^2}{GM}R^3$, if the mass (M) of the central body is larger, the orbital period (T) will be shorter.
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A planet is discovered orbiting a star that is twice as massive as our Sun, but at the same orbital radius as Earth. How would the planet's orbital period compare to Earth's?
According to $T^2 = \frac{4\pi^2}{GM}R^3$, if the mass (M) of the central body is larger, the orbital period (T) will be shorter.
What physical quantity must be present for an object to maintain a circular orbit?
A centripetal force, provided by gravity in the case of an orbit, must be present to cause the necessary centripetal acceleration.
What is tangential acceleration?
Tangential acceleration is the rate at which an object's speed changes and is directed tangent to the object's circular path.
What can cause centripetal acceleration?
Centripetal acceleration can result from a single force, more than one force, or components of forces exerted on an object in circular motion.
An object in circular motion triples its speed while keeping the radius constant. By what factor does its centripetal acceleration change?
Since $a_c = v^2/r$, tripling the speed (v) increases the centripetal acceleration by a factor of $3^2$, or 9.
If a car travels at a constant speed around a circular track, what is its tangential acceleration?
Since tangential acceleration is the rate of change of speed, an object moving at a constant speed has a tangential acceleration of zero.
What is uniform circular motion?
It is the motion of an object traveling in a circular path at a constant speed.
According to the orbital period equation, if two satellites orbit the same central body but one has a larger orbital radius, which one has a longer period?
According to $T^2 \propto R^3$, the satellite with the larger orbital radius (R) will have the longer orbital period (T).
What is the formula for the magnitude of centripetal acceleration?
The magnitude is the ratio of the object's tangential speed squared to the radius of the circular path: $a_c = \frac{v^2}{r}$.
When does an object in circular motion have both centripetal and tangential acceleration?
An object has both when it is changing its speed while moving in a circular path (non-uniform circular motion).
Does an object in circular motion always have a centripetal acceleration?
Yes, any object moving along a circular path must have a centripetal acceleration to continuously change its direction of velocity.
For a satellite in a circular orbit, what force is responsible for its centripetal acceleration?
For a satellite in a circular orbit around a central body, its centripetal acceleration is caused only by gravitational attraction.
State Kepler's third law for a satellite in a circular orbit.
The period (T) and radius (R) of a circular orbit are related to the mass of the central body (M) by the equation: $T^2 = \frac{4\pi^2}{GM}R^3$.
How do the directions of centripetal and tangential acceleration vectors compare?
Centripetal acceleration is directed radially toward the center of the circle, while tangential acceleration is directed tangent to the circular path.
What terms are used to describe the revolution of an object in uniform circular motion?
The revolution of an object traveling in a circular path at a constant speed can be described using its period and frequency.
What is centripetal acceleration?
Centripetal acceleration is the component of an object's acceleration directed toward the center of the object's circular path.