ast 180- ch 3 review

In an ellipse, the ratio of the distance between the foci and the length of the major axis is called: A the eccentricity B the semi-major axis C perihelion D the astronomical unit E Newton's ratio

A

The planet in our solar system with the shortest period of revolution is: A Mercury B Pluto C Jupiter D Venus E you can't fool me, all the planets have the same period of revolution

A

After a long night of cramming for a test, your college room-mate hits his head forcefully against the wall of your room in despair. According to Newton's 3rd Law, as he exerts a force against the wall, there must be an equal and opposite force. How does that opposite force show itself in this case? A Your room-mate is pulled downward by gravity B The wall exerts a force on your room-mate's head and he has a headache C The wall has a huge dent in it D There is an exception to the Law for solid objects like walls, so there is no opposite force E The resident assistant assigned to your floor makes a complaint against the two of you

B

Newton's reformulation of Kepler's third law allows us to measure the masses of bodies in orbit around each other, if we can measure: A the rotation rate of each object B the distances and periods of revolution C the eccentricities and semi-major axes D the force and the reaction force E the sweetness of those fig-filled cookie bars

B

The Earth's escape speed (the speed you need to get away forever) is about 25,000 miles per hour. Escape speed depends on the gravity of the object trying to hold the spacecraft from escaping. Based on your understanding of gravity, how will the escape speed from the Moon compare to the escape speed from Earth? A The Moon's escape speed will be greater than Earth's B The Moon's escape speed will be smaller than Earth's C The Moon's escape speed will be exactly the same as Earth's D The Moon's escape speed will change depending on whether it's a crescent Moon or a full Moon E The Moon's escape speed will be balanced by the Earth being so close and it will be zero

B

The asteroid belt is A a region of icy chunks of material beyond the orbit of Pluto B a zone where rocky chunks orbit between Mars and Jupiter C a series of orbital zones around the Moon, from which fragments drop down to form craters D is a region around the Earth from which meteors (shooting stars) are observed to drop E a new fashion accessory being sold by NASA to raise funds for future missions

B

The idea that objects (in the absence of an outside force) tend to continue doing what they are already doing is called the law of A eccentricity B inertia C action-reaction D angular momentum E Congressional action

B

Why do satellites launched into low-Earth orbits not remain there indefinitely? A they do not have enough speed to fall freely around the Earth B they tend to collide with other spacecraft and spacecraft fragments C they lose speed due to friction with the upper layers of the Earth's atmosphere D they run out of fuel, and without fuel, all satellites, no matter what their orbit is, must fall E this is an unsolved problem, but a NASA committee has been assigned to work on it

C

According to Kepler's third law, there is a relationship between the time a planet takes to revolve around the Sun and its A size B period of rotation C distance from the Sun D eccentricity E astrological sign

C

When NASA and a group of astronomers sent up a spacecraft designed to find planets orbiting other stars, they named it after Kepler. Why was this an appropriate name? A Kepler used his telescope to find the first planet orbiting another star B Kepler was the first person to express the law of universal gravity in mathematical terms C Kepler figured out the rules of planetary motion, which planets in our solar system and planets elsewhere must obey D Kepler was the first person to suggest how to launch rockets into space E Kepler designed the first telescope ever built

C

When a comet like Comet Hale-Bopp comes closest to the Sun in its orbit, we say that it is at: A circular satellite velocity B the minimum angular momentum point C perihelion D apogee E the tail end of its journey

C

Which of the following statements about the force of gravity is FALSE? A it is a universal force, which acts everywhere in space B its strength decreases as the square of the distance C its strength is inversely proportional to the mass: the more mass, the less gravity D the force never becomes zero E it causes the paths of the planets to be ellipses and not straight lines

C

Why do astronauts (and cans of soft drink) float around in the Shuttle instead of falling? A the Shuttle is so far from the Earth, gravity is negligible B the Shuttle's gravity balances the Earth's, so that the net gravity is zero C the Shuttle is falling around the Earth (and everything aboard is in free fall) D the Shuttle has an antigravity device on board, developed by NASA E the rules Newton developed for gravity only hold on Earth, not once you get into space

C

According to Kepler's 2nd Law, comets (which have eccentric orbits) should spend a lot more of their time: A close to the planets B close to the Sun C losing angular momentum D far from the Sun E increasing the rate at which they spin

D

An astronomy textbook, when printed out, weighs four pounds on the surface of the Earth. After finishing your course, you are so tired of the book, you arrange for NASA to shoot it into space. When it is twice as far from the center of the Earth than when you were reading it, what would it weigh? (Note, assume that the book has been moving away from the Earth, not falling freely around it.) A 4 lbs B 8 lbs C 2 lbs D 1 lb E 16 lbs

D

The first artificial satellite the human race lofted into orbit was called: A Pioneer B Explorer C Newton D Sputnik E Luna

D

The planet Neptune was discovered by means of: A careful observations of its motion by one astronomer in England (done over most of his lifetime) B observations of its motion performed over many years by astronomers all over the globe C radio observations of its large magnetic field D mathematical calculations of how it was perturbing the motion of a neighbor planet E discrepancies in the horoscopes of famous actors and actresses; errors in the horoscopes showed astrologers that there must be another cosmic influence on their love lives

D

To come up with the precise mathematical form of his law of gravity, Newton first had to invent the mathematical techniques that we now call: A algebra B ratio and proportions C angular momentum D calculus E scientific notation

D

We now know that the orbit of a stable planet around a star like the Sun is always in the shape of: A a circle B a parabola C a straight line D an ellipse E none of the above

D

When a planet, in its orbit, is closer to the Sun, it: A moves slower than average B reflects less sunlight than average C feels less gravitational pull than average D moves faster than average E spins faster on its axis

D

In Newton's Law of Gravity, the force of gravity goes up as the: A mass goes down B distance goes up C mass goes up D distance goes down E more than one of the above

E

To figure out what you weigh on the surface of the Moon (how much gravity there pulls you downward), you need to know A just the mass of the Moon B just the distance from the Moon's center to its surface C just the size of the Moon's orbit around the Earth (its semi-major axis, say) D which part of its orbit the Moon is in E two of the above factors

E

Which of the following has the greatest density? A a cubic meter of snow B a cubic meter of air C a cubic meter of astronomy textbooks (the printed versions, not the on-line ones) D a cubic meter of feathers E a cubic meter of lead

E

Which of the following statements about forces is FALSE? A forces change the momentum of a body B forces cause an acceleration to take place C forces always occur in equal and opposite pairs D where there is no force, objects continue to move the way they were moving E there are places on Earth where all forces are absent

E