Physics Exam 1

Science

organized body of knowledge
about the natural world

Metaphysics

deals with
things that cannot be
observed physically

The theory of special
relativity was created
by thinking

“outside
the box.”

direct proportion

one increases the
other increases as well

inverse proportion

one quantity
increases, the other decreases

fact

something that can be observed
and agreed to be true.Facts can change

hypothesis

educated guess

hypothesis that is tested again and
again and has not been contradicted

a law

theory

combination of facts and laws
that can be used interpret observations

Aristotle believed in

an earth-centered
universe.

Copernicus

hypothesized
that the Earth is one of
several planets that orbit
(circle) the sun

Natural motion

movement that happens on its own without any pushes, pulls or outside forces.

Violent Motion

any movement caused by an external push or pull

Galileo proposed

the concept of inertia

Inertia

property of objects to
maintain their state of motion

The more matter something has, the more

inertia it has

Mass

measurement of inertia

Weight

force on an object due to gravity

volume

amount of force an object occupies

Density

measure of how much mass occupies a given space

Mass is measured in

kilograms

Forces are measured in

Newtons

The weight of 1 kilogram of mass

9.8 N
or roughly 10 N

1 kg weighs

2.2 lbs. (1 lb = 4.45N)

net force

total forces acting on an
object

A vector quantity

has magnitude (how much) and
direction (which way)

When the net force on an object is equal
to zero, it is

in equilibrium

static equilibrium

it doesn’t move

normal force

a force
from surfaces in contact.

Tension

force from
strings and ropes

Friction always acts

in the direction
opposite the motion

object that moves at
constant velocity

dynamic equilibrium

Distance is measured in

meters (m)

Time is measured in

seconds (s).

Speed is measured in

meters per second
(m/s).

Instantaneous speed

speed at a
given moment of time

Displacement

change in
position

Velocity

speed and direction, also a vector quantity

When the acceleration is in the same
direction as the initial velocity

speeds up

When the acceleration is in the opposite
direction as the initial velocity

slows down

Free-fall

only force acting on
an object is gravity

An object in free fall accelerates towards
the earth at

9.8 m/s/s or about 10 m/s2