Question

kepler’s laws of planetary motion
johannes kepler (1571–1630) made the crucial breakthrough that planets move in elliptical, rather than circular, orbits. using the precise observational data collected by tycho brahe, kepler formulated three laws of planetary motion:

1. first law (law of ellipses): planets move in elliptical orbits, with the sun located at one of the two foci, or gravitational centers. this explained the varying distances between a planet and the sun.
2. second law (law of equal areas): a line connecting a planet to the sun sweeps out equal areas in equal times, meaning that planets move faster when they are closer to the sun (the gravitational center) and slower when they are farther away.
3. third law (harmonic law): the square of a planets orbital period is proportional to the cube of the semi - major axis of its orbit, allowing astronomers to calculate the relative distances and periods of planets based on observational data. this meant that a planet further away will take longer to go around the sun.

kepler’s laws revolutionized astronomy and established the framework for understanding the motion of celestial bodies, including planets and comets.
which law explains why mars has a shorter period of revolution (time required to go around the sun) than saturn?
a) first law
b) second law
c) third law
which law explains why a planet moves faster when it is 13 million km from the sun as opposed to 15 million km from the sun?
a) first law
b) second law
c) third law

Explanation:

1. The Third Law relates the orbital period of a planet to the size of its orbit. Mars is closer to the Sun than Saturn, so according to the Third Law, it has a shorter period of revolution.
2. The Second Law states that a planet moves faster when closer to the Sun. When a planet is 13 million km from the Sun (closer) compared to 15 million km (farther), it moves faster due to the Second Law.

Answer:

1. c) Third Law
2. b) Second Law