Planetary motion
The path a planet takes around the Sun as it revolves.
orbit
The two primary physical factors that affect a celestial body's surface gravity.
mass and radius
What happens to the gravitational attraction between two objects if the mass of one increases
the force increases (gets stronger)
The measure of the amount of matter in an object vs. the gravitational pull acting upon it.
difference between mass and weight
The geometric shape of Earth's orbital path around the Sun.
ellipse or elliptical
What happens to the gravitational force between Earth and Sun if the Sun becomes more massive?
The force increases (gets stronger)
Why gravity between a student's hand and a dropped ball doesn't stop the ball from falling.
Earth's massive pull completely overwhelms it
Universal law stating all objects attract with a force proportional to mass & inverse to distance squared.
Newton's Law of Universal Gravitation
The astronomical term for a celestial body spinning completely around on its own internal axis.
rotation
What happens to the gravitational attraction if Earth is moved significantly farther from the Sun.
The Force decreases (gets weaker)
Earth's motion if the Sun's gravity suddenly vanished (turned completely off).
travel in a straight line into space (inertia)
How being farther from the Sun affects both a planet's orbital path length and its orbital speed.
Longer path and slower speed (longer period)
The specific scientific term for the time it takes a planet to complete one full revolution around the Sun.
orbital period/year
How the strength of a star's gravitational pull influences the orbital speed and period of orbiting planets.
Stronger gravity creates faster speed & shorter periods
The two competing principles/forces that continuously balance to keep planets in stable orbit.
Gravity and inertia (forward momentum)
The instrument used to measure weight by calculating the gravitational downward pull on an object
spring scale
Pluto is called a
Dwarf planet
What is radius
Distance from the center
Why astronauts inside the International Space Station appear weightless even though Earth's gravity is still pulling on them.
free fall (they are falling around Earth at the same speed as the station)
Why an astronaut weighs 68.4 lbs on both Mars & Mercury, even though Mars has nearly 2x the mass
Mars's larger radius places surface further from center