Universal Gravitation and Orbital Motion Flashcards

These flashcards cover the fundamental vocabulary and mathematical concepts of Newton's Law of Universal Gravitation, focusing on mass, distance, and orbital mechanics.

Gravity

A force of attraction where everything in the universe that has mass attracts everything else that also has mass.

Factors affecting gravity

The strength of gravity between two objects, such as a planet and a star, is determined only by mass and distance.

Newton's Law of Universal Gravitation

The law discovered by Newton that identifies mass and distance as the two factors affecting the strength of gravity.

Relationship between mass and gravity

A direct relationship where more mass results in stronger gravity; for example, a bowling ball has more gravity than a baseball.

Relationship between distance and gravity

An inverse relationship where objects closer together have stronger gravity, and objects further away have weaker gravity.

Effect of increased Sun mass on orbits

If the Sun were to get bigger, the increased gravity would pull orbits in closer, making them smaller.

Effect of decreased Sun mass on orbits

If the Sun were to get smaller, the decreased gravity would cause orbits to become wider or larger.

Reason satellites do not crash into Earth

Satellites move at such high speeds that the direction of gravity keeps changing; they are never in one spot long enough to be pulled straight down.

Average satellite speed

Even the slowest satellites move at approximately $7,000 ext{ miles per hour}$, which is fast enough to maintain orbit.

$$F_g$$

The symbol representing gravitational force in the universal gravitation equation.

$$G$$

The universal gravitational constant, which always equals $6.67 imes 10^{-11}$.

$$r$$

The variable representing the distance between two objects, which must be squared in the denominator of the gravitation formula.

Calculation if distance is halved

When distance is multiplied by one-half, the denominator becomes (rac{1}{2})^2 or $0.25$, requiring the force to be divided by $0.25$ (effectively multiplying by $4$).

Calculation if mass is tripled

If one mass ($m_1$ or $m_2$) is multiplied by $3$, the gravitational force on the other side of the equation must also be multiplied by $3$, resulting in a triple force.

Moon mass (Ruth example)

$7.34 imes 10^{22} ext{ kg}$.

Moon to Earth distance (Ruth example)

$3.825 imes 10^{5} ext{ m}$.

Ruth's mass (lecture example)

$27 ext{ kg}$ (approximately $60 ext{ pounds}$).

Titan

A moon that orbits the planet Saturn in a nearly perfect circle.