Force of Gravity
A planet has a mass of 2.6 x 1024 kg and another has a mass of 9.17 x 1022 kg. Calculate the force of gravity if the distance between the planets is 6.35 x 108 m.
3.94 x 1019 N
The Danish noble who built an observatory on the island of Hven and whose data became the basis for the planetary laws of motion.
Who is Tycho Brahe?
Kepler's First Law, also known by this other name, states that:
What is the law of ellipses; planets move in elliptical orbits with the Sun at one focus of the ellipse?
Increasing this value will increase force of gravity.
Mass.
Name two ways to increase acceleration due to gravity on the surface of a planet.
Decrease radius/distance to center or increase mass of the planet.
Two planets are 2.41 x 109 m apart and have identical masses of 8.41 x 1025 kg. What is the force of gravity between the two planets?
8.12 x 1022 N
The astronomer who famously published the 3 planetary laws of motion.
Who is Johannes Kepler (Germany ftw)?
Kepler's Second Law, also known as this, states the following:
What is The Law of Equal Areas; An imaginary line extending from the Sun to an orbiting body sweeps out equal area in equal time?
Increasing this variable will decrease force of gravity.
Distance
Two moons orbiting a planet have the same mass, but one is twice as far as the other. Which moon experiences a greater force of gravity from the planet?
The moon that is closer to the planet.
The force of gravity from a planet acting on an asteroid is 4.79 x 1012 N. If the asteroid has a mass of 8.21 x 1012 kg and the planet has a mass of 9.34 x 1020 kg, calculate the distance between the asteroid and the planet.
3.268 x 105 m = 326786 m
Between the beginning of Tycho Brahe's observations and Johannes Kepler publishing his laws, roughly this number of years passed.
What is 40 years?
Kepler's Third Law, the Law of Harmonies, relates the orbital periods of planets to their distance from the Sun. This proportional relationship becomes an equivalency if the period and distance are expressed in these units.
What are Earth years and astronomical units?
Solve the Fg equation for r. (get r by itself)
r = sqrt(G*m1*m2/Fg)
A planet orbits a star and travels from point A to point B, which takes twice as long as it does to travel from point C to point D. Which segment will have a greater area?
Segment A to B.
The force of gravity on a brick on Earth is 14 N. The mass of the Earth doubles. What is the new force of gravity on the brick if the radius of the Earth does not change?
28 N
Known as "The First Scientist and The Last Magician," this British commoner is published La Principia Mathematica, in which he established the three laws of motion.
Who is Sir Isaac Newton?
What is Kepler's 2nd Law, and what is a high degree of eccentricity?
Solve the Fg equation for m, if the planets have the same mass.
m = sqrt(Fg*r2/G)
The Earth has an orbital period of 52 weeks and an orbital radius of 1 AU. Earth's moon has an orbital period of about 4 weeks. Can we solve for the orbital radius of the moon with this information?
No. The moon is not orbiting the same object as the Earth.
The force of gravity on a dog is 40 Newtons when it is on the surface of the Earth. What would the new force of gravity be if the radius of the Earth shrunk by one half? (r is divided by two)
160 N
What is 1687?
The orbital period of Mars is 1.88 Earth years. What is the orbital radius of Mars?
What is 1.52 AU?
Solve the force of gravity equation for m1 if both planets have different masses.
m1=Fg*r2/(G*m2)
A newly discovered planet has the same acceleration due to gravity as the Earth, but the radius of the planet is twice as big as Earth's. How much bigger should the mass of this new planet be?
What is four times the mass?