Astronomy (Multiple Choice)

4 PointsScientific models are used to ________.

1. present the scale of the solar system to the general public
2. make miniature representations of the universe
3. make specific predictions that can be tested through observations or experiments
4. prove that past paradigms no longer hold true

4 PointsScientific thinking developed only in the past few decades.

1. True
2. False

4 PointsKepler’s third law, p2 = a3, means that

1. a planet’s period does not depend on the eccentricity of its orbit.
2. all orbits with the same semimajor axis have the same period.
3. planets that are farther from the Sun move at slower average speeds than nearer planets.
4. All of these are correct.
5. the period of a planet does not depend on its mass.

4 PointsWhich of the following statements expresses what we mean by a scientific theory?

1. an explanation for a physical phenomenon, an explanation that hasn’t been tested yet
2. an educated guess
3. a simple model that explains a wide variety of phenomena and that has survived repeated tests

4 PointsGalileo challenged the idea that objects in the heavens were perfect by ________.

1. observing sunspots on the Sun and mountains on the Moon
2. proving Kepler’s laws were correct
3. showing that heavy objects fall at the same rate as lighter objects
4. inventing the telescope

4 PointsKepler developed his model of elliptical orbits because of an 8-arcminute discrepancy between observations and a model of planetary motion with circular orbits.

1. True
2. False

4 PointsNewton’s second law states: sum of forces = mass × acceleration. According to this, what property can you determine if you observe the acceleration of an object with a known mass?

1. the current location of the object
2. the value of a single force acting on the object
3. the current velocity of the object.
4. the sum total of all forces acting on the object

4 PointsSpeed and velocity are the same thing.

1. True
2. False

4 PointsWhy are astronauts weightless in the Space Station?

1. because the Space Station is traveling so fast
2. because the Space Station is moving at constant velocity
3. because the Space Station is constantly in free-fall around the Earth
4. because there is no gravity in space

4 PointsMomentum is defined as ________.

1. mass times speed
2. force times velocity
3. mass times acceleration
4. mass times velocity

4 PointsIf an object’s velocity is doubled, its momentum is

1. quadrupled.
2. halved.
3. dependent on its acceleration.
4. unchanged.
5. doubled.

4 PointsWhat do we mean by a geocentric model of the universe?

1. a model designed to explain what we see in the sky while having the Earth located in the center of the universe
2. a model designed to explain what we see in the sky while having the Earth orbit the Sun
3. a model of the Milky Way Galaxy that has our solar system located at its center
4. the name given to sphere-shaped models that show all the constellations as they appear in our sky on the celestial sphere

4 PointsWhat was the Ptolemaic model?

1. the first scientific model to successfully predict solar and lunar eclipses
2. the Earth-centered model of the cosmos in which the Earth was surrounded by seven perfect spheres, one each for the Sun, Moon, Mercury, Venus, Mars, Jupiter, and Saturn
3. an Earth-centered model of planetary motion published by Ptolemy
4. a Sun-centered model of planetary motion published by Ptolemy

4 PointsColumbus was the first person to discover that Earth is round.

1. True
2. False

4 PointsHe developed a system for predicting planetary positions that remained in use for some 1,500 years.

1. Tycho Brahe
2. Kepler
3. Ptolemy
4. Copernicus
5. Galileo

4 PointsTo measure the mass of an astronomical object, one can observe the orbital period and distance of a companion.

1. True
2. False

4 PointsWhat do we mean by the orbital energy of an orbiting object (such as a planet, moon, or satellite)?

1. Orbital energy is the amount of energy required for the object to leave orbit and escape into space.
2. Orbital energy is a measure of the object’s speed as it moves through its orbit.
3. Orbital energy is the object’s kinetic energy as it moves through its orbit.
4. Orbital energy is the sum of the object’s kinetic energy and its gravitational potential energy as it moves through its orbit.

4 PointsWhat quantities does angular momentum depend upon?

1. momentum and angular velocity
2. mass and velocity
3. force, velocity, and radius
4. mass, velocity, and radius
5. force and radius

4 PointsConsider the elliptical orbit of a comet around the Sun. Where in its orbit does it have the largest amount of total orbital energy?

1. It always has the same total orbital energy.
2. when it is closest to the Sun
3. when it is farthest from the Sun

4 PointsWhich of the following best describes the origin of ocean tides on Earth?

1. Tides are caused by the difference in the force of gravity exerted by the Moon across the sphere of the Earth.
2. Tides are caused by the 23.5-degree tilt of the Earth’s rotational axis to the ecliptic plane.
3. The Moon’s gravity pulls harder on water than on land, because water is less dense than rock.
4. Tides are caused on the side of the Earth nearest the Moon because the Moon’s gravity attracts the water.

4 PointsAccording to the universal law of gravitation, the force due to gravity is

1. inversely proportional to the square of the distance between objects.
2. directly proportional to the distance between objects.
3. not dependent on the distance between objects.
4. inversely proportional to the distance between objects.
5. directly proportional to the square of the distance between objects.

4 PointsNewton’s version of Kepler’s third law states: p2 = × a3In this equation, what does p represent?

1. the masses of the two objects
2. the average distance between the two objects
3. the orbital period
4. the universal gravitational constant

4 PointsRadiative energy is ________.

1. energy from nuclear power plants
2. energy carried by light
3. energy of motion
4. heat energy

4 PointsConsidering Einstein’s famous equation, E = mc2, which of the following statements is true?

1. Mass can be turned into energy, but energy cannot be turned back into mass.
2. One kilogram of mass represents 1 joule of energy.
3. It takes a large amount of mass to produce a small amount of energy.
4. You can make mass into energy if you can accelerate the mass to the speed of light.
5. A small amount of mass can be turned into a large amount of energy.

4 PointsAbsolute zero is ________.

1. 0° Celsius
2. 0° Fahrenheit
3. 0 Kelvin
4. 100° Celsius