#### General Principles

The amount of energy absorbed per unit mass of tissue at a given site: expressed in roentgens.

dose

A unit that measures a quality by itself, without using any other fundamental unit, such as length, mass, time, and temperature;

Fundamental Quality also called base unit or base quantity.

Abbreviated as the letter m and measured in kilograms (kg); a measure of a body's inertia; dependent on the amount of matter in an object. It's similar to weight, but weight changes with the amount of gravity, while this unit stays the same.

mass

A unit of measurement that combines two or more fundamental units; examples are units that measure density or velocity.

derived quantity

The speed at which an object is moving. It is measured by determining the distance an object travels in a specific period of time. Waves in the electromagnetic spectrum all travel at the speed of light, or 3 x 108 meters per second. In the SI system this unit is measured in m/s.

velocity

A rate of change in velocity, measured in meters per second squared (m/sec2).

acceleration

An action that changes the motion of an object. This unit equals mass times acceleration measured in Newtons

Force (F)

Abbreviated as the letter p; the product of mass (m) times velocity (v).

momentum

In radiation biology, the product of absorbed dose in rads and the modifying factors, namely the quality factor (QF), distribution factor (DF), and any other necessary factors. The unit of dose equivalent is the rem.

dose equivalent

In radiology, a measure of the x-ray or gamma radiation at a certain place based on its ability to cause ionization. The unit of exposure is the roentgen. Symbol X. Called also exposure dose.. The special unit of exposure is the roentgen (R). 1R = 2.58 x 10-4 C/kg. In the international system (SI unit), the special unit is coulomb per kilogram.

exposure

General term for the processes by which atoms with unstable nuclei radiate excess energy in the form of particles and energy.

Anything that exists in physical form and has mass; a solid, liquid, or gas.

matter

The ability to do work or to change something. It can take the form of mechanical, heat, light, or electrical energy and is measured in the SI unit called the joule (J).

energy

The application of force to an object; the product of force times the distance the object is moved. The SI unit of is the joule.

work

The rate at which work is done, defined as work divided by time. measured in watts

power

What is the formula for velocity?

V=d/t

What is the formula for acceleration?

a=Vt-Vo/t

What is the formula for force?

F=ma

What is the formula for momentum

p=mv

What is the formula for work?

work=fd

What is the formula for power?

P=work/t

The property of an object with mass to resist a change in its state of motion. Objects at rest will continue to stay at rest, and objects in motion will continue to move at the same velocity and direction.

inertia

A body will remain at rest or continue to move with constant velocity in a straight line unless acted on by an external force.

Newton's First Law: Inertia

Einstein's famous equation (E=mc^2)

Mass-Energy Equivalence

energy resulting from a chemical reaction.

chemical energy

the energy resulting from the flow of electricity.

electrical energy

the energy resulting from the motion of atoms or molecules.

thermal energy

a form of energy that exists as an electric and magnetic disturbance.

Electromagnetic energy

2 states of energy

potential kinetic

Stored energy; abbreviated as PE. PE = mgh.

potential energy

The energy of an object in motion; abbreviated as KE. KE = 1/2 mv2.

kinetic

The unit that is used to measure the intensity of radiation; abbreviated as R. It takes 1 R of radiation energy to ionize a certain number of atoms in a certain volume of air.

roentgen

The unit that measures the x-ray radiation energy absorbed in the body. The SI unit is the gray (Gy). Both units measure the amount of energy absorbed per unit of mass (kg).

It is a measure of radiation exposure in occupational settings: the amount of radiation absorbed by those who work around it. The SI unit is the seivert (Sv).

rem

A measure of the rate of radioactive decay; the amount of material that has 37 billion nuclei decaying in 1 second; abbreviated as Ci.

curie

In radiology, a measure of the x-ray or gamma radiation at a certain place based on its ability to cause ionization. The unit of exposure is the roentgen. Symbol X. Called also exposure dose. The specialunit of exposure is the roentgen (R). 1R = 2.58 x 10-4 C/kg.

Coulomb/kilogram

A unit of absorbed radiation dose equal to 100 rads. Abbreviated Gy.

gray

The SI unit of radiation absorbed dose equivalent, defined as that producing the same biologic effect in a specified tissue as 1 gray of high-energy x-rays; equals 100 rem.

sievert

A unit of radioactivity, defined as that of quantity of a radioactive nuclide whose rate of spontaneous nuclear transformation is one decay event per second (1 s-1); 1 curie equals 3.7 x 1010 becquerels; 1 microcurie equals 37 kilobecquerels.

becquerel

A unit of measure is a value agreed upon by a society to give meaning to a quantity.
True False

true

Which system uses the force of gravity to define mass?

British System

What is the velocity of an object if it travels 50 meters in 5 seconds?

10 m/s

What is the force necessary to move a 100 kg object at a rate of 3 meters/second?

300 Newtons

What is the work done if a force of 300 N is applied over a distance of 15 meters?

4,500J

What is the power consumed if 500 J of work is done in 4 seconds?

125 W