Which planet’s orbit was Kepler first studying when he began to develop his laws of orbital motion?(1 point)

None of the above planets. Kepler's laws were developed by studying the orbit of Mars.

Which of these describes Kepler’s third law of orbital motion?(1 point)

Responses

T∝a2
T∝a2

T2∝a
T2∝a

T3 ∝a2
T3 ∝a2

T2 ∝ a3

T2 ∝ a3

Which statement describes Kepler’s third law of orbital motion?(1 point)

Responses

The cube of orbital period is proportional to the square of the semi-major axis.
The cube of orbital period is proportional to the square of the semi-major axis.

The square of orbital period is proportional to the cube of the semi-major axis.
The square of orbital period is proportional to the cube of the semi-major axis.

The orbital period is proportional to the square of the semi-major axis.
The orbital period is proportional to the square of the semi-major axis.

The square of orbital period is proportional to the semi-major axis.

The cube of orbital period is proportional to the square of the semi-major axis.

Which orbital shape did most scientists in the early 1600s think the planets of our solar system have?(1 point)

Responses

hyperbolic
hyperbolic

parabolic
parabolic

elliptical
elliptical

circular

circular

Which is the best description of Earth’s orbit?(1 point)

Responses

highly elliptical
highly elliptical

almost circular
almost circular

parabolic
parabolic

circular

almost circular

The correct answer is Mars. Kepler first began studying the orbit of Mars when he started developing his laws of orbital motion. Kepler made detailed observations of Mars' position in the sky over a series of years, and these observations helped him formulate his laws that describe the motion of planets around the Sun.