Physics 8.01 Quiz-History of Gravitation, Physics 8.04 Quiz-Universal Gravitation, Physics 8.05 Quiz-Einstein and the Gravitational Field
Features of a field diagram
-The field at each point is a vector that points in the direction that a test mass placed at that point would be pulled. -The field has a magnitude at each point that depends only on position and on the mass that produced the field, but not on the mass that experiences the force from the field. -The magnitude of the field decreases with distance from the mass that is the source of the field. This is represented by the decreasing length of the field vector arrows. -The gravitational field has dimensions of force divided by mass, N / K g, which is equivalent to m / s squared.
The centers of two 15.0 kg spheres are separated by 3.00 m. The magnitude of the gravitational force between the two spheres is approximately
1.67 × 10-9 N
A satellite is in geosynchronous orbit around earth, so that it stays above the same point on earth and has a period of exactly one day. Another satellite orbits earth at a distance twice as far from earth's center. What is the period of the second satellite? Assume the radius of earth is 6,378 km and the mass of each satellite is 200 kg.
2.8 days.
An astronaut weighs 800 N on the surface of earth. What is the weight of the astronaut 6.37 × 106 m above the surface of the earth? Assume the radius of earth is 6,378 km.
200 N
A mass of 10.2 kg is in a gravitational field of 3.30 m/s 2. What force acts on the mass?
33.7 N
What is gravity?
A force between objects because of their mass
Who introduced the idea that mass affects time and space?
Albert Einstein
Who challenged the idea that the sun revolved around the earth?
Copernicus
What is Kepler's first law?
Each planet moves in an elliptical orbit, with the sun at one focus of the ellipse.
Which of these does Newton's law of universal gravitation imply?
Earth's gravity acts on people inside a space station orbiting the earth.
Who explained gravitation, and the gravitational field, by assuming that mass distorts the space and time around it?
Einstein
What is the "special relativity" theory?
Einstein's theory of how time and space measurements change when viewed in different coordinate systems moving at constant velocity with respect to each other.
Newton's law of universal gravitation
Fg=G m1m2/r2 with G as a constant that applies to all masses and exprsses the strength of the gravitational force.
Newton's law of universal gravitation
Fα 1/ r2 where r is the distance between any two objects with mass. The force of gravity gets weaker between the two objects as they move farther apart, and stronger as they come closer together.
Newton's law of universal gravitation
F∝m1m2 where m1 and m2 are the masses of the two objcts.The force of gravity therefore is stronger if the masses are larger.
Who developed an outstanding, detailed experiment to measure G?
Henry Cavendish
Kepler's laws described how the planets moved, but not why—who later developed theories about the planets moved in these ways?
Isaac Newton
What is "universal" about Newton's law of universal gravitation?
It applies to any two objects at any location.
What causes gravity, according to Einstein's theory of general relativity?
Mass bending space and time
Who suggested that around any particle that has an electric charge there is an electric field?
Michael Faraday
What did Cavendish use to measure the mass of the earth?
Newton's law of universal gravitation
Which of these is not evidence confirming Einstein's explanation of gravity?
Newton's third law of motion
Who hypothesized that the stars moved around the earth on crystal spheres?
Plato and Aristotle
Which of the following terms is associated with Einstein?
Special relativity
If you plotted vector arrows at selected points around a mass to represent the gravitational field vectors, how should the arrows change as the points for which they are drawn become more distant from the mass that produces the field?
The arrows would become shorter.
A 60.0 kg student is standing on the pavement outside. To use Newton's law of universal gravitation to find the weight of the student, you should calculate the weight as the force of attraction between the student and what?
The entire earth, located one earth radius away.
Which of these discoveries is generally attributed to Newton?
The force of gravity acts between any two objects.
Which of these discoveries is generally attributed to Kepler?
The orbit of Mars is an ellipse.
Which of these best describes earth's gravitational field?
The property at each point of space that describes the force a mass would experience.
What is Kepler's second law?
The radius from the focus to the location of the planet sweeps out equal areas in equal times. (in this elliptical orbit, a planet moves faster when it is closer to the sun.)
Who's work provided evidence that the stars were not perfect and eternal?
Tycho Brahe's
What did Ptolemy develop?
a complicated system to describe the complex motions of planets
gravitational field
a property that exists at every point of the space around a mass, producing a force on other masses
field
a property that has a value at each point in space
Johannes Kepler
analyzed the extensive data of Brahe and found that Brahe's data for the motion of Mars were impossible to explain unless he assumed, contrary to previous ideas, that the orbit of Mars was elliptical rather than circular.
law of universal gravitation
any two objects in the universe exert a force on each other based on their masses
the force of gravity is an ______________ force between any two masses
attractive
An electric field can
be described by the effect of an electric charge on the space around it.
a region in space where it is theorized that no mass or light can escape
black hole
Newton's three laws in a stationary coordinate system, but this fails to work for the equations describing
electric and magnetic fields and light.
the realization that any two objects in the universe exert an attractive force on each other because of their mass is called the force of
gravity
what force caused the planetary and orbital motion described by Kepler?
gravity
force of gravity between two objects is _________________________ to the square of the distance between them
inversely proportional
Whereas an electric field surrounds an electric charge, a gravitational field surrounds any
mass
the force is greater between
objects closer to each other and between objects of larger mass.
What is Kepler's third law?
planets with smaller orbit radii travel around the sun in a much shorter time than planets with larger orbits.
What does the bending of space-time do?
produces gravitational forces and causes objects to accelerate
the gravitational force between any two objects is ______________ to the product of their masses
proportional
what stated that space and time are not independent, and that mass warps four dimensional space-time?
space-time
What two efforts deepened Newton's understanding of gravity?
the effort to understand the motion of objects on the earth, and to understand the motions of the planets
space-time
the four-dimensional fabric of space
electric field
the influence throughout a space due to one or more electrically charged particles or surfaces
