Chapter 8-Forces in Nature
inertia
a body's tendency to maintain its velocity
kinematics
a branch of the science of mechanics which seeks merely to describe motion
dynamics
a branch of the science of mechanics which seeks to describe motion by describing its causes
force
a push or a pull
friction
acts against every object in motion in the opposite direction to slow it down
neutral equilibrium
an object in this state can be overturned without changing the height of its center gravity
stable equilibrium
an object in this state is not easily tipped over
unstable equilibrium
an object in this state is upset at the slightest disturbance
static equilibrium
an object that remains at rest within earth's gravitational field
instability
an unsupported center of gravity and the point where the force of gravity is effectively applied would be free to move downward, in the direction of the applied force.
Ptolemy
conceived the idea of the geocentric model solar system
geocentric
earth centered
universal law of gravitation
law that states that every object in the universe was attracted to every other object with a force (gravity) that is directly proportional to the product of their masses and inversely proportional to the square of the distances between them.
Copernicus
proposed the heliocentric model of the solar system
gravity
refers to the attractive force exerted by a planet, a star, or other celestial body upon objects near their surfaces
gravitation
refers to the attractive force that exists between any two masses
center of gravity (CG)
represents the combined effect of gravity on all of the particles in an object
kinetic friction
resistance to sliding
static friction
resistance to start sliding
heliocentric
sun centered
mass
the amount of matter in an object
perihelion
the closest position to the sun in the planet's orbit
aphelion
the farthest position from the sun in the planet's orbit
gravitational field
the field of attractive force caused by gravity near a large mass
weight
the force exerted on an object's mass by the earth's gravity
normal force
the force of the surface against weight of the object and always acts perpendicular to the surface
weak force
the fundamental force is responsible for certain particle interactions in the radioactive decay of atomic nuclei
electromagnetic force
the fundamental force that exists only between electrically charged bodies
law of areas (Kepler's second law of planetary motion)
the law that states that the line joining the planet to the sun traces out equal areas in equal times
law of orbits (Kepler's first law of planetary motion)
the law that states that the orbit of the planet is elliptical
law of periods (Kepler's third law of planetary motion)
the law that states that, for any planet, the square of the period of revolution is proportional to the cube of the average distance from the sun
inertial mass
the object's mass when measured at rest
center of mass
the point in an object that describes the combined effect of all the individual particles of mass
strong force
the strongest of the fundamental forces, and holds the nucleus of an atom together
period
the time required to complete one orbit about the sun
gravitational force
the weakest of all fundamental forces, exists between any two bodies of matter