Motion of Orbiting Satellites - AP Physics C: Mechanics
Card 1 of 30
What is the significance of a geostationary orbit?
What is the significance of a geostationary orbit?
Tap to reveal answer
It has a period equal to Earth's rotation period. Satellite remains fixed above same Earth location.
It has a period equal to Earth's rotation period. Satellite remains fixed above same Earth location.
← Didn't Know|Knew It →
Identify the expression for total mechanical energy of a satellite in orbit.
Identify the expression for total mechanical energy of a satellite in orbit.
Tap to reveal answer
$E = -\frac{GMm}{2r}$. Sum of kinetic and gravitational potential energies.
$E = -\frac{GMm}{2r}$. Sum of kinetic and gravitational potential energies.
← Didn't Know|Knew It →
Which force provides the centripetal force for an orbiting satellite?
Which force provides the centripetal force for an orbiting satellite?
Tap to reveal answer
Gravitational force. Earth's gravity provides the centripetal force for circular orbits.
Gravitational force. Earth's gravity provides the centripetal force for circular orbits.
← Didn't Know|Knew It →
Find the gravitational force on a satellite of mass $m$ orbiting Earth.
Find the gravitational force on a satellite of mass $m$ orbiting Earth.
Tap to reveal answer
$F = \frac{GMm}{r^2}$. Newton's law of gravitation with Earth's mass $M$ and distance $r$.
$F = \frac{GMm}{r^2}$. Newton's law of gravitation with Earth's mass $M$ and distance $r$.
← Didn't Know|Knew It →
State Kepler's Third Law.
State Kepler's Third Law.
Tap to reveal answer
$T^2 \text{ is proportional to } r^3$. Square of period proportional to cube of semi-major axis.
$T^2 \text{ is proportional to } r^3$. Square of period proportional to cube of semi-major axis.
← Didn't Know|Knew It →
State Kepler's Second Law.
State Kepler's Second Law.
Tap to reveal answer
A line joining a planet and the Sun sweeps out equal areas in equal time intervals. Conservation of angular momentum causes variable orbital speeds.
A line joining a planet and the Sun sweeps out equal areas in equal time intervals. Conservation of angular momentum causes variable orbital speeds.
← Didn't Know|Knew It →
State Kepler's First Law of planetary motion.
State Kepler's First Law of planetary motion.
Tap to reveal answer
Planets move in elliptical orbits with the Sun at one focus. Describes elliptical shape with Sun at focal point.
Planets move in elliptical orbits with the Sun at one focus. Describes elliptical shape with Sun at focal point.
← Didn't Know|Knew It →
Identify the expression for the orbital speed of a satellite.
Identify the expression for the orbital speed of a satellite.
Tap to reveal answer
$v = \frac{2 \pi r}{T}$. Circumference divided by period for uniform circular motion.
$v = \frac{2 \pi r}{T}$. Circumference divided by period for uniform circular motion.
← Didn't Know|Knew It →
What is the formula for gravitational potential energy of a satellite?
What is the formula for gravitational potential energy of a satellite?
Tap to reveal answer
$U = -\frac{G M m}{r}$. Negative value indicates bound system with zero reference at infinity.
$U = -\frac{G M m}{r}$. Negative value indicates bound system with zero reference at infinity.
← Didn't Know|Knew It →
State the formula for the centripetal force acting on a satellite in orbit.
State the formula for the centripetal force acting on a satellite in orbit.
Tap to reveal answer
$F = \frac{mv^2}{r}$. Force directed toward center required for circular motion.
$F = \frac{mv^2}{r}$. Force directed toward center required for circular motion.
← Didn't Know|Knew It →
What is the formula for gravitational force between two masses?
What is the formula for gravitational force between two masses?
Tap to reveal answer
$F = G \frac{m_1 m_2}{r^2}$. Newton's law of universal gravitation between two point masses.
$F = G \frac{m_1 m_2}{r^2}$. Newton's law of universal gravitation between two point masses.
← Didn't Know|Knew It →
What is the gravitational constant $G$?
What is the gravitational constant $G$?
Tap to reveal answer
$6.674 \times 10^{-11} \text{ N m}^2/\text{kg}^2$. Universal gravitational constant in SI units.
$6.674 \times 10^{-11} \text{ N m}^2/\text{kg}^2$. Universal gravitational constant in SI units.
← Didn't Know|Knew It →
What happens to the period of orbit if the mass of the satellite increases?
What happens to the period of orbit if the mass of the satellite increases?
Tap to reveal answer
The period remains unchanged. Period depends only on orbital radius, not satellite mass.
The period remains unchanged. Period depends only on orbital radius, not satellite mass.
← Didn't Know|Knew It →
What is the condition for a geosynchronous orbit?
What is the condition for a geosynchronous orbit?
Tap to reveal answer
Orbital period is 24 hours. Matches Earth's rotational period for stationary positioning.
Orbital period is 24 hours. Matches Earth's rotational period for stationary positioning.
← Didn't Know|Knew It →
Identify the relation between gravitational potential and distance from Earth's center.
Identify the relation between gravitational potential and distance from Earth's center.
Tap to reveal answer
$V = -\frac{G M}{r}$. Gravitational potential energy per unit mass.
$V = -\frac{G M}{r}$. Gravitational potential energy per unit mass.
← Didn't Know|Knew It →
Which force provides the centripetal force for an orbiting satellite?
Which force provides the centripetal force for an orbiting satellite?
Tap to reveal answer
Gravitational force. Earth's gravity provides the centripetal force for circular orbits.
Gravitational force. Earth's gravity provides the centripetal force for circular orbits.
← Didn't Know|Knew It →
What is the effect of increasing altitude on orbital speed?
What is the effect of increasing altitude on orbital speed?
Tap to reveal answer
Orbital speed decreases. Higher orbits have slower speeds per $v = \sqrt{GM/r}$.
Orbital speed decreases. Higher orbits have slower speeds per $v = \sqrt{GM/r}$.
← Didn't Know|Knew It →
What is the formula for gravitational force between two masses?
What is the formula for gravitational force between two masses?
Tap to reveal answer
$F = G \frac{m_1 m_2}{r^2}$. Newton's law of universal gravitation between two point masses.
$F = G \frac{m_1 m_2}{r^2}$. Newton's law of universal gravitation between two point masses.
← Didn't Know|Knew It →
What is the expression for kinetic energy of a satellite in orbit?
What is the expression for kinetic energy of a satellite in orbit?
Tap to reveal answer
$K = \frac{1}{2} \frac{GMm}{r}$. Half the gravitational potential energy magnitude.
$K = \frac{1}{2} \frac{GMm}{r}$. Half the gravitational potential energy magnitude.
← Didn't Know|Knew It →
Identify the expression for angular velocity of a satellite in orbit.
Identify the expression for angular velocity of a satellite in orbit.
Tap to reveal answer
$\text{Angular velocity} = \frac{2 \pi}{T}$. Rate of angular displacement for orbital revolution.
$\text{Angular velocity} = \frac{2 \pi}{T}$. Rate of angular displacement for orbital revolution.
← Didn't Know|Knew It →
What is the gravitational field strength at distance $r$ from a planet?
What is the gravitational field strength at distance $r$ from a planet?
Tap to reveal answer
$g = \frac{GM}{r^2}$. Gravitational acceleration at any distance from planet center.
$g = \frac{GM}{r^2}$. Gravitational acceleration at any distance from planet center.
← Didn't Know|Knew It →
What is the effect on orbital period if the mass of the planet increases?
What is the effect on orbital period if the mass of the planet increases?
Tap to reveal answer
The period decreases. Larger planetary mass creates stronger gravitational field.
The period decreases. Larger planetary mass creates stronger gravitational field.
← Didn't Know|Knew It →
What is the formula for the centripetal acceleration of a satellite in orbit?
What is the formula for the centripetal acceleration of a satellite in orbit?
Tap to reveal answer
$a_c = \frac{v^2}{r}$. Acceleration toward center for circular orbital motion.
$a_c = \frac{v^2}{r}$. Acceleration toward center for circular orbital motion.
← Didn't Know|Knew It →
What happens to the orbital speed if the radius of orbit increases?
What happens to the orbital speed if the radius of orbit increases?
Tap to reveal answer
Orbital speed decreases. Inverse relationship from $v = \sqrt{GM/r}$ formula.
Orbital speed decreases. Inverse relationship from $v = \sqrt{GM/r}$ formula.
← Didn't Know|Knew It →
Calculate the gravitational force on a satellite at height $h$ above Earth.
Calculate the gravitational force on a satellite at height $h$ above Earth.
Tap to reveal answer
$F = \frac{GMm}{(R + h)^2}$. Gravitational force decreases with square of distance.
$F = \frac{GMm}{(R + h)^2}$. Gravitational force decreases with square of distance.
← Didn't Know|Knew It →
What is the semi-major axis for a circular orbit?
What is the semi-major axis for a circular orbit?
Tap to reveal answer
It is equal to the orbital radius. Semi-major axis equals radius for circular orbital geometry.
It is equal to the orbital radius. Semi-major axis equals radius for circular orbital geometry.
← Didn't Know|Knew It →
What is the consequence of a satellite losing energy in orbit?
What is the consequence of a satellite losing energy in orbit?
Tap to reveal answer
It will spiral inward. Energy loss causes orbital decay toward the planet.
It will spiral inward. Energy loss causes orbital decay toward the planet.
← Didn't Know|Knew It →
Identify the relation between gravitational potential and distance from Earth's center.
Identify the relation between gravitational potential and distance from Earth's center.
Tap to reveal answer
$V = -\frac{G M}{r}$. Gravitational potential energy per unit mass.
$V = -\frac{G M}{r}$. Gravitational potential energy per unit mass.
← Didn't Know|Knew It →
What is the specific energy of a satellite in orbit?
What is the specific energy of a satellite in orbit?
Tap to reveal answer
$\text{Specific energy} = -\frac{GM}{2r}$. Total energy per unit mass for orbital motion.
$\text{Specific energy} = -\frac{GM}{2r}$. Total energy per unit mass for orbital motion.
← Didn't Know|Knew It →
What is the condition for a geosynchronous orbit?
What is the condition for a geosynchronous orbit?
Tap to reveal answer
Orbital period is 24 hours. Matches Earth's rotational period for stationary positioning.
Orbital period is 24 hours. Matches Earth's rotational period for stationary positioning.
← Didn't Know|Knew It →