Laws of Motion

Question 1

What does keplers 3rd law say mathematically?

Answer 1

The square of a planet’s sidereal period around the sun is directly proportional to the cube of the length of it’s orbits semi-major axis. P^2=a^3

Question 2

What is aphelion?

Answer 2

Speed is smallest when the planet is at furthest distance

Question 3

What values can eccentricty have?

Answer 3

An ellipse with eccentricity=0 is a circle. As the ellipse becomes longer and skinnier,
like a circle that’s being flattened more and more, the eccentricity approaches ‘ 1 ‘.

Question 3

What is Newton’s Law of Inertia?

Answer 3

A body remains at rest or moves in a straight line at a constant speed unless acted upon by an unbalanced outside force

Question 4

What is eccentricity?

Answer 4

Degrees of variance from a circle

Question 5

How does kepler’s 2nd law define speed of a planet?

Answer 5

Astronimical Unit : Which is the average distance from the earth to the sun- 1.5x10^8th power KM Light Year (LY): Which is the distance traveled by light in one year - 9.5x10^12 power KM (63000 AU) Parsec (pc): distance at which two objects seperated by 1AU appear 1 arcsec apart- 3.1x10^13KM (3.26 ly)

Question 6

What is kepler’s first law?

Answer 6

The orbit of each planet about the sun is an ellipse with the sun at one focus. (A planet’s distance from the sun varies during it’s orbit).

Question 7

What is an astronomical unit?

Answer 7

The average distance fro the eath to the sun -1.5x10^8KM

Question 8

What’s is Newton’s 2 law of motion?

Answer 8

The force on an object is equal to the mass of the object times the accelerationdie to the force (w/ acceleration being the change in velocity w/time). Force=Mass x Acceleration

Question 10

What are major and minor axes?

Answer 10

Long and short dimensions of the ellipse

Question 11

What defines and Ellipse?

Answer 11

A type of oval that happens to be the shape of bound orbits. An ellipse can be drawn by moving a pencil along a string whose ends are ties to two tacks; the location of the tacks are the focus of the ellipse. (A set of points for which the sume of the distances from two specific points focus is constant)

Question 12

What is Kepler’s 3rd law?

Answer 12

More distant planets orbit the sun at a slower average speed, obeying the precise mathematical relationships

Question 13

What is perihelion?

Answer 13

Speed of a planet is highest when the planet is closest to the sun

Question 14

What are retrograde motions?

Answer 14

Motion in the direction opposite to the movement of something else and is the contrary of direct or prograde motion. Motion - Orbit of one body about another or about some other point. Rotation - of a single body about it’s axis or other phenomena such as precession or rotations of the axis

Question 15

What is newton’s 3rd law?

Answer 15

Whenever one body exerts a force on a second body , the second body exerts an equal and opposite force on the first.

Question 16

How do the phases of venus relate to it’s orbit around the sun?

Answer 16

Heliocentric model relates to the phases of venus and it’s relative size. The clear correlation is explained by venus orbiting the sun. Mercury and venus are never in opposition (opposite side of the earth from the sun is a clue).

Question 17

What is Kepler’s 2nd law?

Answer 17

As a planet moves around it’s orbit, it sweeps out equal areas in equal times. (The planet moves a greater distance when it is near the sun than it does further from the sun.

Question 18

Describe Newton’s law of gravity

Answer 18

The force between two bodies is directly proportional to the masses of eacg, and in versely proportional to the square of the distance between them. F12-Gm,m^2/r^2 (G= 6.67 x 10^-11 m^3/Kg S^2)= Gravitational constant