Universal Gravitation
This fundamental force of attraction exists between any two objects with mass in the universe.
What is gravity (or gravitational force)?
The acceleration due to gravity on Earth's surface has this approximate numerical value in meters per second squared.
What is 9.81 m/s^2?
Escape velocity is the minimum speed an unpowered object needs to break free from this type of field created by a celestial body.
What is a gravitational field?
In the equation F = ma, the letter m stands for this, and the letter a stands for this.
What is mass and acceleration?
Weight is a force measured in Newtons, while this property measures the total amount of matter in an object and remains constant anywhere in the universe.
What is mass?
According to the inverse-square law, if you triple the distance between two planets, the gravitational force drops to this fraction of its original value.
What is 1/9 (one-ninth)?
If a planet has the same mass as Earth but twice the radius, its surface gravity ($g$) is this fraction of Earth's surface gravity.
What is 1/4 (one-fourth)?
An astronomical object whose escape velocity exceeds the speed of light (c) is classified as this object.
What is a black hole?
If a constant thrust force is applied to a space probe whose mass decreases as it burns fuel, the probe's acceleration will do this.
What is increase?
As a satellite moves into a higher orbit farther from a central body, its circular orbital velocity does this.
What is decrease (it moves slower)?
If you keep the distance constant but double the mass of one planet in a binary system, the gravitational force changes by this factor.
What is a factor of 2 (it doubles)?
These collapsed stellar remnants have extreme surface gravity primarily because their massive solar material is packed into a tiny radius of around 10 kilometers.
What are neutron stars?
Between Earth, the Sun, Jupiter, and the Moon, this body has a significantly lower escape velocity due to its lower mass and smaller size.
What is the Moon?
The SI unit of force, named after the physicist who formulated these laws of motion.
What is the Newton (N)?
To double the orbital force of attraction between two planets by changing only distance, you must multiply the original distance by this factor.
What is 1/sqrt(2) or approximately 0.707?
This is the number for the universal constant, represented by the uppercase letter G
An astronaut weighs 600 N on Earth. On a world with one-third Earth's surface acceleration, the astronaut would weigh this much.
What is 200 N?
If a planet's mass quadruples (4 times) while its radius stays constant, its escape velocity increases by this factor.
What is a factor of 2 (it doubles)?
A 1,500 kg satellite is experiencing a forward thruster force of 500 N. Calculate the magnitude of the satellite's net acceleration.
What is 0.33 m/s^2?
This key difference in formula structure separates surface gravity (g = GM/r^2) from escape velocity (v_e = sqrt(2GM/r) regarding the radius r.
What is g depends on r^2 while v_e depends on r (inside a square root)?
Two small moons of mass 1.0 x 10^15 kg and 2.0 x 10^15 kg are separated by 1.0 x 10^6 m. Calculate the gravitational force between them to one decimal place.
What is 1.3348 * 10 ^ 8 N?
Planet Y has a mass of 6.0 x 10^24 kg and a radius of 3.0 x 10^6 m. Calculate its surface gravity g (rounded to the nearest whole number).
What is 44 x m/s ^ 2?
Calculate the escape velocity of a moon with mass M = 7.35 x 10 ^ 22 kg and radius r = 1.74 x 10^6 m in km/s (rounded to one decimal place).
What is 2.4 km/s or 2,376 m/s?
An ion thruster pushes a 1,200 kg space probe with a constant force of 0.06 N. Find the probe's acceleration in scientific notation.
What is 5.0 x 10 ^ -5 m/s ^ 2?
The theoretical radius around a compact mass where the escape velocity exactly equals the speed of light is known by this term.
What is the Event Horizon (or Schwarzschild radius)?