Newton's Law of Gravitation: Definition & Example
Which of the following orbital eccentricities is NOT an elliptical orbit?
1
A planet is orbiting its star at a maximum radius of 1.2 x 10^7 meters. If the mass of the star is 2 x 10^30 kg, what is the time period of the orbit?
22.6 seconds
Object A has a mass of 3 x 10^10 kilograms, and object B has a mass of 8 x 10^10 kilograms. If they are 8,000 meters apart, what is the gravitational attraction between them? (G = 6.67 x 10^-11)
2500 N
A metal bar is positioned near the Sun. If the mass of the metal bar is 20,000 kilograms, the mass of the Sun is 2 x 10^30 kilograms, the distance to the nearside of the bar from the Sun is 100,000 meters, and the length of the bar is 300 meters, what is the force of gravity between the Sun and the bar?
266,001,994,017,946 newtons.
A planet is orbiting its star at a maximum radius of 1.2 x 10^7 meters. If the mass of the star is 2 x 10^30 kg, and the current radius is 0.9 x 10^7 meters, what is the velocity of the orbit?
4.3 x 10^6 meters per second.
You lift a 3kg dumbbell from the ground until it is above your head, at a height of 1.5 meters. How much energy did you use in the process? (Assume that you're not a space alien, and your gym is on Earth.)
44 Joules
A 10 kg bowling ball is lifted from the ground to a height of 1 meter. Assuming the bowling alley is on Earth, how much gravitational potential energy does it now have?
98 Joules
If all of the objects have around the same mass, which of the following objects has the most gravitational potential energy?
A ball stuck on the roof of a two-story house
In general, what are Kepler's Laws?
A series of laws that describe the motion of orbiting bodies no matter the shape of the orbit.
If a planet has an orbital eccentricity equal to 0.70, then its orbit is:
A very elongated ellipse
What kind of relationship does gravity follow with distance?
An inverse-square relationship
What is an extended object?
An object that is not spherical, or uniform in shape, and cannot be treated as a point mass.
What is an elliptical orbit?
An orbit between a circle and a parabola in shape (but not including a parabola). LESS THAN ONE!
How do we know that gravitational potential energy exists?
Because when you drop a ball, it starts to move, and this energy has to come from somewhere.
Which of these describes the basic idea of how calculus is used to find the gravitational force due to an extended object?
Breaking an object into mass elements, and integrating to get the total of the forces on all those elements.
This is the extent to which an orbit deviates from a circle:
Eccentricity
The planets in our solar system all have ___orbits:
Elliptical
What is Newton's Law of Universal Gravitation in words?
Every body in the universe attracts every other body, with a force that is proportional to the product of their masses, and inversely proportional to the square of the distance between them.
A __is one of two fixed points from which an ellipse can be generated:
Focus
If a car is rolling naturally downhill without the engine running, what energy transfer is happening?
Gravitational potential energy is changing into kinetic energy.
If the distance between two objects is doubled, and the mass of one of the objects is doubled, what happens to the gravitational force?
It reduces to a half.
If you increase the distance between two objects by a factor of three, what happens to the force between them?
It reduces to a ninth.
What is Newton's Law of Gravitation?
It says that every object in the universe attracts every other object.
Which of the following is an assumption of Newton's Universal Law of Gravitation that doesn't EVER apply to an extended object?
Masses can be taken as point masses.
A planet's average distance from the sun is equal to the:
Semimajor axis