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ST Science midterm

weeks 1_5

QuestionAnswer
Work (TQ) expanded energy in order to accomplish something
Work in Physics expended energy is a force applied to an object is to moved, and the accomplishment is that the object moves a distance
Formula for Work (TQ) force x distance
Joule (TQ) the coventional unit for work and energy
Joule a metric unit for work and is defined as a force of one newton acting over a distance of one meter, where the force and the distance moved lie in the same direction
Work VS Energy in order to do work, an object must have energy in order to have energy, an object must have work done to it.
Power if a 10-newton force is applied to an object, moving it 10 meters in 10 seconds, the person has done 100 joules of work
Formula for Power work divided by time
Unit for Power is watt
How many watts of power in one horsepower 746
THE AVERAGE HORSEPOWER A NORMAL HUMAN CAN GENERATE OVER A FEW MINUTES one third, one tenth of horsepower for any greater length of time
CONSERVATION OF ENERGY throughout the entire universe, there is a fixed amount of energy and it will never change
CONSERVATION OF ENERGY energy cannot be created or destroyed; it can only be changed from one form of energy to another
4 TYPES OF SIMPLE MACHINES 1)inclined plane 2)lever 3)wheel and axle 4)pulley
INCLINED PLANES useful when attempting to lift something that is very heavy
INCLINED PLANES requires less force, although the distance up the ramp is greater than the distance straight up into the truck
WEDGE an inclined plane that can be moved
LEVER a simple machine that consists of a rigid bar supported at a point known as the fulcrum
LEVER effort force is applied at one point on the lever in order to move an object, known as the resistance force, located at some other point on the lever.
CLASS-ONE LEVER (TEETER-TOTTER) levers in which the fulcrum is somewhere between the point of applied force and the point of exerted force
CLASS-ONE LEVER (TEETER-TOTTER) consist of an effort arm where force is applied by the user, a pivot point called the fulcrum, and a resistance arm where the object to be lifted or moved is placed
CHARACTERISTICS OF A CLASS-ONE LEVER fulcun in the middle, effort on one side, resistance (load force)on the extreme side
SECOND CLASS LEVER is a lever in which both the effort and resistance forces (load force)are on the same side of the fulcrum, with the resistance force between the fulcrum and effort force
CHARCATERISTICS OF A SECOND CLASS LEVER fulcrum on one end, load force (resistance)in the middle, effort force o the other end (extreme side)
WHEELBARROW (2ND CLASS) fulcrum is the wheel, the resistance (load force) is the dirt, and the effort is the handle
THIRD-CLASS LEVER has both forces on the same side of the fulcrum, but in this class, the resistance force (load force)is farther away from the fulcrum than the effort force
Characteristics of Third-Class Lever fulcrum in on side, load force (resistance) opposite extreme side
Speed The distance an object travels during a particular time interval
Velocity In addition to how fast the object travels, also defines the direction in which the object moves
Acceleration How quickly an object changes velocity
Light Speed 3 x 10 ^8 or 300, 000 km/sec
First Law of Motion (Inertia) Is an objects resistance to to changing its motion; how much inertia an object has is determined by the objects mass
Second Law of Motion Mass of an object is held constant, the larger the force that applied, the greater the acceleration
Third Law of Motion Equal and opposite forces occur when two or more objects interact
Friction When two or more objects interact, their irregular surfaces sllide and scrape against one another, impeding the motion of objects. Force that opposes the motion.
Free Fall Occurs when an object is pulled down by the gravitational force of the Earth or any other large gravitational body
Terminal Velocity The maximum speed that a person or object can achieve while falling toward the Earth
Pressure The amount of force that is applied to a specific area.
Mass The measurement of an objects inertia, which is dependant on the amount of matter that an object possesses
Weight Dependant upon how much mass an object has
Momentum A value that describes the amount of inertia and motion an object has
Impulse Describes how a change in momuentum occurs. In order to change an objects motion or momentum, a force need to be applied to the object for a period of time.
Vector Is a quantity that has magnitude and direction, velocity is a vector
Rotation Is to spin about an axis located within the spinning object
Revolution Takes place when an object turns about an axis that is located outside the object
Centripetal Force "Center Seeking" force causes objects to travel in a circular path
Centrifugal Force The sensation that a person feels when traveling in a circular path. "Pulled Out" away from the center.
Torque A force that, when applied to An object, causes a turning motion
Lever_Arm Distance between the axix of rotation and the point where the force is applied.
Pulley A wheel (with an axle or bearing in it's center) on the rim which rides a rope or cord
Wheel A circular disk or rim attached to a central rod, called an axle, about which the wheel can turn
Gears A by-product of the wheel and axle, can produce huge mechanical advantages in machines. Consist of a circular wheel with teeth carved into them
Kinetic Energy Transferred into heat from the friction between air molecules nd the object
Alternetive Energy Any form of energy that doesnt orginate from fossil fuels
Hydroelectric Energy Generated by sending high speed, high-kinetic energy water through a series of turbines that changes the waters kinetic energy into useable electrical energy
Heat The amount of internal kinetic energy of atoms and molecules that flows from a warmer to a cooler environment in an effort to reach equilibrium
Measured in calories Heat
Temperature Is a scale for measuring thermal energy
Calorie The amount of heat needed to increase one gram of water by one degree Celsius or Kelvin
Fahrenheit A scale in which the freezing point of water was 32*F and the boiling point was 212*F
Thermographs Detect the amount of heat emanating from objects or regions, use colors to determine the temperature
Thermometers Measure the heat energy released from an object
Thermostat Not only measures the temperature, but also controls heating and cooling systems
Celsius Scale based on the freezing point of water (0*C) and boiling point of water (100*C)
Kelvin Absolute zero is a theoretical temperature indicating zero heat energy
States of matter Solid (ice), Liquid (water), Gas (steam), Plasma (ionized gas)
Plasma Occurs when the atoms in a gaseous molecule become ionized, or charged particles
Convection Circulating warm, transfers through movement
Conduction Acheived through contact with a warm surface; no movement
Infrared radiation Exposure to electromagnetic radiation; specifically infrared waves
Thermodynamics The field of physics that studies the movement of heat
Zeroth Law States that temperature is a method of determining if heat will flow from one object to another.
First Law of Thermodynamics Energy can be neither created nor destroyed, but only transformed. One form of energy is changed to another.
Second Law of Thermodynamics States that heat will only flow freely from a warm object to a cool environment
Entropy; also 2nd Law of Thermodynamics Amount of disorder in a system. The closer it gets to equilibrium it becomes more disordered increasing entropy
Third Law of Thermodynamics States that absolute zero, the lowest possible temperature, the point at which there is no energy, can never be reached
Electrostatic Study of those electrically charged particles that can be moved from place to place and then held at rest
Magnets Consists of tiny, aligned magnetic domains inside materials such as iron
Magnetic domains Atoms that have electrons each with a North and South pole spinning the same direction
Magnetic field Electrons spinning in the opposite directions
The key to magnetism is the uniform motion of electrons
Electromagnetic waves Created by the the vibrations of electric charge
Electromagnet An iron core wrapped up in electrical, current carrying wire
Insulators Inhibit the movement of electricity; non metals
All forces including electrical forces are measured in Newtons
Electrical field An area where there is an attractive or repulsive electric force between two or more charged particles
Anode (+) Always pulls negative charges
Cathode (-) Always pulls positive charges
Electrical current A flow of positive/negative charges; measured in amps
Voltage Potential difference in an object or battery
Resistance Slows down the electric charges and in the process causes wires or any of the conductor of electricity to heat up
Semiconductors Allow electrical current to trabel without resistance
Voltage, current, and resistance Form the basic law of circuits
Voltage Current (X) resistance
Watt Unit for Power
Kilowatt 1,000 watts of power
Voltage supply Potential difference in the circuit
Current flow Wires are needed to connect the power supply to the resistors and back to the power supply
Resistance The flow of electrons can be acheived with wires, electrical devices, and even the power itself
Electrical current Closed path through which current travels
Direct current Allow electrons to travel only in one direction throughout a circuit
Alternating current Vibrates the electrons in the circuit back and forth 60 times a second
Semi-Conductors A few free electrons that flow freely in the material such as Germanium and silicone
Series Circuit Consist of electrical devices (resistors, capacitors, batteries, switches) arranged in a single line
Parallel circuit Allows the electricity to flow through different branches
Wave A traveling disturbance that moves energy from one location to another without transferrig matter
Two major wave classifications Longitudinal and transvers
Compression Medium in longitudinal waves pushes close together at some points
Rarefaction Separates from eachother immediately after
Velocity of wave Depend upon the material or medium in which it is traveling; typically the denser and more elastic the medium, the faster the wave will travel
Frequency How many cycles of vibration occur per second and is measured in cycles per second or Hertz
Period Amount of time it takes a wave to vibrate one full cycle
Wave with a long period has a low frequency, while a wave with a very short period has a high frequency
Light, radio, x-rays Electromagnetic wave
Electomagnetic wave Consist of two perpendicular waves, one component of the wave being a vibrating electric field while the other is a corresponding magnet field
Does not need a medium such as air, water, or steel to travel Electromagnetic wave
Radio wave Wave transmitted is electromagnetic waves. NOT sound waves
Hz = Hertz Unit for frequency
Hertz represents the number of vibrations or cycles per second of a wave
KHz Kilo or 1,000 hertz
Mhz Megahertz or one million hertz
Ghz Gigahertz or one billion
Microwave (SHF; super high frquency) Electromagnetic waves in a frequency range of 3Ghz to 30Ghz
Created in klystron and magnetron electron tubes Microwaves
Damping Gradual decrease in wave amplitude
Amplifiers Typically used to increase the amplitude of the waves before damping reduces the waves to nothing
Standing waves Occur when a continuous set of waves reflect off a surface and overlap eachother
Nodes Sections that stay still
Anti-nodes Sections between nodes that move up and down dramatically
Resonance Occurs when the frequency of a continuous wave achieves a standing wave with maximum amplitude
Transformers Used to match impedances when mechanical waves encounter new media; provides smoother gradual transition
Transducer To change one type of wave into another. i.e. telephones, speakers
Radar A frequency band on the electromagnetic spectrum, is an acronym for Radio Detection and Ranging
Doppler effect The change in frequency of a wave that results from an objects changing position relative to an observer
Sound Travel at 340 m/s or 760 mph
Human ears Between 20Hz and 20,000Hz
Ultrasonic Those frequencies above the human bardwidth of hearing (20,000Hz)
Sonar Acronym for Sound Navigation Ranging is a method of sound waves to determine the distance an object is from a transmitter of sound
Ultrasound Systems direct high frequency sound (usually between 5-7Mhz) into particular regions of the body, and measure the time it takes for the sound wave to reflect back to the machine
Infrasonics (subsonic) Sounds are those frequencies below the human hearing. Less than 20Hz
Sound intensity is the energy of the sound wave. For sound and mechanical waves, the energy is determined by the height of its amplitude
Pitch of Sound The combination of frequency and intensity
Doppler effect Demonstrates that a waves length decreases as the source moves toward an observer, and increases when the source moves away
The inverse square law Sound intensity diminishes according to the inverse square law, which states that the intensity of a sound is inversely proportional to the square of the distance
Decibal The loudness of a sound is increased by a factor of ten
The speed of sound, approximately 331 m/s at 0*C is considered Mach 1
Acoustics The branch of physics that deals with the science of sound
Created by: E.Ochoa