59 terms

# summary of terms physics exam

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Fact
a phenomenon about which competent observers who have made a series of observations are in agreement with
Hypothesis
An educated guess
Law
a general hypothesis or statement about the relationship of natural quiantities that has been tested over and over and has not been contridicted
Law
Also known as principal
psuedoscience
Fake science that pretends to be real science
Scientific method
principals and procedures for the systematic pursuit of knowledge
Theory
a synthesis of a large body of information that encompasses well-tested and verified hypothesis.
Newtons first law of motion
Every object continues in its state of rest, or in uniform motion in a straight line, unless compelled to change that state by forces impressed upon it.
Inertia
the property of things to resist change
Force
a push or a pull
Net force
The vector sum of forces that act on an object
Mechanical equilibrium
The state of an object or a system to of pbjects where there is no change in motion.
Equilibrium rule
For anything in equilibrium the sum of the forces is zero
Speed
how fast something moves
velocity
The speed and direction of an object
Vector quantity
has both magnitude and acceleration
Acceleration
The rate at which velocity changes
Free Fall
motion under the influence of only gravity.
Friction
The resistance force that opposes motion
mass
The amount of matter in an object
weight
the force due to gravity
Kilogram
unit of mass
Newton
a unit of force
Volume
the quantity of space an object takes up
Newtons second law
The acceleration of an object is directly porportional to the net force acting on the object
Force
any influence that can cause an object to accelerate
Terminal speed
when air resistance is equal to weight in a falling object
Terminal velocity
when direction is specified and air resistance is equal to weight in a falling object
Newtons third law
Whenever one object exerts a force on the other object, the second object exerts an equal and opposite force
Vector quantity
both magnitude and direction
Scalar quantity
just magnitude and no direction
Vector
an arrow drawn to represent a vector quantity
Resultant
The net result of two or more combined vectors.
momentum
The product of the mass of an object and its velocity
Impulse
The product of force acting on an object and the time during which it acts.
Law of conservation of momentum
momentum before=momentum after
Elastic collision
when there is no heat and the objects do not stick together
Inelastic collision
when there is heat and the two objects stick together
Work
w=fd
power
p=work/time
Energy
the property of a system that enables it to do work
Mechanical energy
Energy due to the position of something
potential energy
the energy that something poses because of its position
Kinetic energy
energy of motion
conservation of energy
energy cannot be created nor destroyed but simply transformed into something else
machine
a device that increases or decreases force
conservation of energy for machines
The work output cannot exceed the work input
lever
simple machine that allows pivot
efficiency
the percentage of work put into a machine that is converted into a useful output.
Tangential speed
circular motion
rotational speed
number of rotations per unit of time
rotational inertia
its resistance to change of its state of rotation
torque
t=lever arm x force
center of mass
average position of mass
equilibrium
the state of an object when it is not acted upon by a net force or net torque
centripetal force
force that causes an object to move in a circle
centrifugal force
imaginary force ex. you when a car turns around a corner
angular momentum
the product of a bodys rotational inertia and rotational velocity about a particular axis.
conservation of angular momentum
when no external torque acts on an object, no change in angular momentum can occur.