Physical Science Terms

Density

the compactness of matter described by a ratio of mass (or weight) per unit volume

Direct Proportion

when two variables increase or decrease together in the same ratio (at the same rate)

English system

a system of measurement that originally used sizes of parts of the human body as referents

Fundamental properties

a property that cannot be defined in simpler terms other than to describe how it is measured; length, mass, time, and charge

Inverse proportion

the relationship in which the value of one variable increases while the value of the second variable decreases at the same rate (in the same ratio)

Metric system

a system of referent units based on invariable referents of nature that have been defined as standards (entire world uses, expect U.S.)

Proportionality constant

a constant applied to a proportionality statement that transforms the statement into an equation

Scientific law

A relationship between quantities described by an equation in physical sciences

Scientific principle

a relationship between quantities concerned with a specific or narrow range of observations and behavior

Variable

a changing quantity usually represented by a letter or symbol

3 properties of motion

speed, velocity, acceleration

Net Force

sum of ALL forces acting on an object

distance

1/2(acceleration)(time)²

d=1/2(a)(t)²

average velocity

final velocity+initial velocity/2

v-bar=vf+vi/2

Compound motion

when an object is projected into the air. split into vertical & horizontal parts. acceleration due to gravity = g (9.8 m/s²)

Newton’s first law of motion

law of inertia.

object will remain in state-of-rest unless a net force acts on it

Newton’s second law of motion

describes relation between net force, mass, and acceleration. F=ma, more force=more acceleration

Newton’s third law of motion

force is produced by the interaction of two different objects.

Equal in size, opposite in direction.

Newton

Force needed to give a 1.0kg mass an acceleration of 1.0m/s²

momentum

momentum=mass x velocity

p=mv

Centripetal force

force that pulls an object out of its straight-line path

force needed to keep depends on the mass, velocity, and radius of the circle

Newton’s Universal Law of Gravitation

relationship between masses of two objects, distance, and proportionality constant

provides the centripetal force that keeps the Moon in orbit.

acceleration

a=vf-vi/t

Centrifugal force

an apparent outward force on an object following a circular path that is a consequence of the third law of motion

Force

a push or pull capable of changing the state of motion of an object; has magnitude (strength) as well as direction

Free Fall

when objects fall toward Earth with no forces acting upward; air resistance is neglected when considering an object to be in free fall

Impulse

a change of motion is brought about by the product of the size of an applied force and the time the force is applied

Mass

a measure of inertia, which means a resistance in the change of motion

Weight

weight=(mass)(gravity)

w=mg

g=9.8m/s²

How is Force, F (newton) calculated

F=ma (general)

or

F=mv²/r (when talking of centripetal forces)

Chemical energy

a form of energy involved in chemical reactions associated with changes in internal potential energy; a kind of potential energy that is stored and later released during a chemical reaction

Electrical energy

a form of energy from electromagnetic interactions;

one of five forms of energy—mechanical, chemical, radiant, electrical, and nuclear

energy

the ability to do work

Geothermal energy

heat from beneath Earth’s surface, usually reaching the surface in the form of geysers, steam, or hot water

Horsepower

a measurement of power defined as a power rating of 550 ft•lb/s

joule

the metric unit used to measure work and energy; can also be used to measure heat; equivalent to newton-meter

joule

the metric unit for measuring work and energy, equivalent to newton-meter.

mechanical energy

the form of energy associated with machines, objects in motion, and objects having potential energy that results from gravity

nuclear energy

the form of energy from reactions involving the nucleus, the innermost part of an atom

potential energy

energy due to position; energy associated with changes in position (e.g., gravitational potential energy) or changes in shape (e.g., compressed or stretched spring)

power

the rate at which energy is transferred; defined as work per unit of time

radiant energy

Energy from electromagnetic radiation (ex: visible light)

watt

the metric unit for power; equivalent to J/s

work

when this is done on an object, it gains energy

Calculate Potential Energy

PE = mgh

(mass)(gravity)(height)

Calculate Kinetic Energy

KE=1/2mv²

Calculate Power

P=work/time

P=w/t

Calculate velocity final (vf)

𝑣𝑓 = √2𝑔ℎ (whole problem is square-rooted)

g=gravity

h=height

Scientific Method

collect observations, develop explanations, and test explanations