Studied by 35 peoplekinematics
the study of motion
motion
a change in an object’s location as measured by a particular observer
distance (d)
the total length of the path travelled by an object in motion
direction
the line an object moves along from a particular starting point
scalar
a quantity that has only magnitude (size)
vector
a quantity that has magnitude (size) and direction
position (d w arrow on top)
the distance and direction of an object from a reference point
displacement (triangle d with arrow on top)
the change in position of an object
vector scale diagram
a vector diagram drawn using a specific scale
directed line segment
a straight line between two points with a specific direction
average speed (Vav)
the total distance travelled divided by the total time taken to travel that distance
average velocity (V with an arrow on top)
the total displacement, or change in position, divided by the total time for that displacement
position–time graph
a graph describing the motion of an object, with position on the vertical axis and time on the horizontal axis
slope (m)
a measure of the steepness of a line
rise
vertical change between two points on a line
run
horizontal change between two points on a line
motion with uniform or constant velocity
motion of an object at a constant speed in a straight line
motion with non-uniform velocity (accelerated motion)
motion in which the object’s speed changes or the object does not travel in a straight line
acceleration (a with arrow on top)
how quickly an object’s velocity changes over time (rate of change of velocity)
velocity–time graph
a graph describing the motion of an object, with velocity on the vertical axis and time on the horizontal axis
motion with uniform acceleration
motion in which velocity changes at a constant rate
instantaneous velocity ( Vnet with arrow on top)
the velocity of an object at a specifi c instant in time
acceleration–time graph
a graph describing motion of an object, with acceleration on the vertical axis and time on the horizontal axi
acceleration due to gravity (g)
the acceleration that occurs when an object is allowed to fall freely; close to Earth’s surface, g has a value of 9.8 m/s2
free fall
the acceleration due to gravity of an object in the absence of air resistance
terminal velocity
the velocity of an object when the force due to air resistance equals the force due to gravity on the object
resultant vector
r a vector that results from adding two or more given vectors
component vectors
vectors which when added together give the original vector from which they were derived; one component is parallel to the x-axis and the other is parallel to the y-axis
projectile
an object that moves along a two-dimensional curved trajectory in response to gravity
projectile motion
the motion of a projectile under gravity
time of flight
the time taken for a projectile to complete its motion
range
the horizontal distance travelled by a projectile
dynamics
the study of the causes of motion
newton (N)
he SI unit of force (1 N = 1 kg·m/s2)
system diagram
a simple sketch of all objects involved in a situation
free-body diagram (FBD)
a simple drawing of an object showing all the forces that are acting on it
applied force (Fa)
a force that results when one object makes contact with another and pushes or pulls on it
tension (FT)
a pulling force from a rope or string on an object that always points toward the rope or string
normal force (FN)
) a perpendicular force exerted by a surface on an object in contact with the surface; the normal force always points away from the surface
friction (Ff )
opposes the sliding of two surfaces across one another; friction acts opposite to the motion or attempted motion
force of gravity (Fg)
force of attraction between any two objects
net force (Fnet)
the sum of all forces acting on an object
inertia
a the property of matter that causes it to resist changes in motion; inertia is directly proportional to the mass of the object
first law of motion
an object will remain at rest or continue to move at constant velocity when the net force on the object is zero
second law of motion
an object will accelerate in the direction of the net force; the magnitude of the acceleration is directly proportional to the magnitude of the net force and inversely proportional to the object’s mass
third law of motion
each action force has a reaction force that is equal in magnitude and opposite in direction
free fall
the motion of a falling object where the only force acting on the object is gravity
terminal speed
the maximum constant speed of a falling object
force field
d a region of space surrounding an object that can exert a force on other objects that are placed within that region and are able to interact with that force
gravitational fi eld strength
the force per unit mass acting on an object when placed in a gravitational field
static friction (Fs with an arrow on top)
a force of friction that prevents the sliding of two surfaces relative to one another
kinetic friction (Fk with an arrow on top)
the force exerted on a moving object by a surface opposite to the direction of motion of the object
coefficient of friction
the ratio of the force of friction to the normal force
coefficient of static friction
the ratio of the maximum force of static friction to the normal force
coefficient of kinetic friction
the ratio of kinetic friction to the normal force
mechanical work (W)
applying a force on an object that displaces the object in the direction of the force or a component of the force
energy
the capacity to do work
kinetic energy (Ek)
energy possessed by moving objects
work–energy principle
the net amount of mechanical work done on an object equals the object’s change in kinetic energy
potential energy
a form of energy an object possesses because of its position in relation to forces in its environment
gravitational potential energy
energy possessed by an object due to its position relative to the surface of Earth
reference level
a designated level to which objects may fall; considered to have a gravitational potential energy value of 0 J
mechanical energy
the sum of kinetic energy and gravitational potential energy
the sum of kinetic energy and gravitational potential energy
the total quantity of kinetic and potential energy possessed by the atoms or molecules of a substance
nuclear energy
potential energy of protons and neutrons in atomic nuclei
energy transformation
the change of one type of energy into another
law of conservation of energy
energy is neither created nor destroyed; when energy is transformed from one form into another, no energy is lost
efficiency
the amount of useful energy produced in an energy transformation expressed as a percentage of the total amount of energy used
energy resource
energy-rich substance
non-renewable energy resource
a substance that cannot be replenished as it is used in energy-transforming processes
renewable energy resource
a substance with an unlimited supply or a supply that can be replenished as the substance is used in energy-transforming processes
fossil fuel
fuel produced by the decayed and compressed remains of plants that lived hundreds of millions of years ago
nuclear fission
the decomposition of large, unstable nuclei into smaller, more stable nuclei
nuclear fusion
a nuclear reaction in which the nuclei of two atoms fuse together to form a larger nucleus
solar energy
radiant energy from the Sun
passive solar design
building design that uses the Sun’s radiant energy directly for heating
photovoltaic cell
a device that transforms radiant energy into electrical energy
hydroelectricity
electricity produced by transforming the kinetic energy of rushing water into electrical energy
power (P)
the rate of transforming energy or doing work
brownout
reduced supply of electricity caused by system damage or excess demand
electrical power grid
a large electricity distribution system composed of a network of electrical power plants and electricity distribution towers and cables
proton
a positively charged particle in the nucleus of an atom
neutron
an uncharged particle in the nucleus of an atom
nucleons
particles in the nucleus of an atom; protons and neutrons
electron
a negatively charged particle found in the space surrounding the nucleus of an atom
ground state
state in which all electrons are at their lowest possible energy levels
excited state
e state in which one or more electrons are at higher energy levels than in the ground state
atomic number
the number of protons in the nucleus
mass number
the number of protons and neutrons in the nucleus
isotope
a form of an element that has the same atomic number, but a different mass number than all other forms of that element
radioisotope
an unstable isotope that spontaneously changes its nuclear structure and releases energy in the form of radiation
radiation
energy released when the nucleus of an unstable isotope undergoes a change in structure
radioactivity
a process by which the nucleus of an atom spontaneously disintegrates
nuclear fission
n the decomposition of large, unstable nuclei into smaller, more stable nuclei
nuclear reaction
the process by which the nucleus of an atom sometimes changes
electrostatic force
the force of attraction or repulsion due to electric charges
strong nuclear force
the very strong force of attraction between nucleons
radioactive decay
the process by which a radioactive atom’s nucleus breaks apart and forms different atoms
alpha (a) decay
nuclear reaction in which an alpha particle is emitted
alpha particle
a particle emitted during alpha decay; composed of a helium nucleus containing two protons and two neutrons
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Flashcard (102)