HBCS 9th Grade Physical Science Final exam study guide – Flashcards
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acid
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substance that produces hydrogen ions (H+) in a water solution
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base
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a substance that produces hydroxide ions (OH-) in a water solution
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properties of acids
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sour tasting; can burn; corrosive; react with indicators to produce color change (red)
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properties of bases
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crystalline solids; slippery; bitter tasting; corrosive; can burn; react with indicators to produce color change (blue)
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salt
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compound formed when negative ions from an acid combine with positive ions from a base
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ionization
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process in which electrolytes dissolve in water and separate into charged particles
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hydronium ion
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H3O+ ion, forms when an acid dissolves in water and H+ ions interact with water
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hydroxide ion
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OH- ion; forms when a base dissolves in water
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pH scale
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a measure of the concentration of hydronium ions in a solution using a scale ranging from 0-14 with 0 being the most acidic and 14 being the most basic
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neutralization reaction
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a chemical reaction that occurs when H3O+ ions from an acid react with the OH- ions from a base to produce water molecules and salt
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electrolyte
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compound that breaks apart in water, producing charged particles (ions) that can conduct electricity
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strong acids
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any acid that dissociates completely in solution
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weak acids
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any acid that only partly dissociates in solution
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weak bases
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any base that does not dissociate completely in solution
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strong bases
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any base that dissociates completely in solution
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indicator
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organic compound that changes colors in acids and bases
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motion
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a change in an object's position relative to a reference point
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displacement
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distance and direction of an object's change in position from the starting point
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vector
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a quantity that has both magnitude and direction
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scalar
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a physical quantity that is completely described by its magnitude
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velocity
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the speed and direction of a moving object
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momentum
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property of a moving object that equals its mass times its velocity
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acceleration
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rate of change of velocity;
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force
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a push or pull exerted on an object
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friction
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force that opposes the sliding motion between touching surfaces
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net force
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sum of all of the forces that are acting on an object
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balanced forces
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forces on an object that are equal in size and opposite in direction; net force will be zero and object won't move
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unbalanced forces
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two forces on an object that are not equal in size and are opposite in direction; the direction of the net force will be the same as the larger force
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gravity
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attractive forces between two objects that depends on the masses of the objects and the distance between them
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weight
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gravitational force exerted on an object
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inertia
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tendency of an object to resist any change to its motion
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work
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transfer of energy when a force is applied over a distance; measure in joules
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machine
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device that makes doing work easier by increasing the force applied to an object, changing the direction of an applied force, or increasing the distance over which a force can be applied
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simple machine
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machine that does work with only one movement; (lever, pulley, wheel ; axle, inclined plane, screw, and wedge)
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pulley
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a simple machine that uses grooved wheels and a rope to raise, lower or move a load. (a modified lever)
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power
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rate at which energy is converted; measured in watts
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screw
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a simple machine that is an inclined plane wrapped around a pole which holds things together or lifts materials.
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inclined plane
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a simple machine consisting of a slanting surface connecting a lower level to a higher level
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wedge
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a simple machine that is an object with at least one slanting side ending in a sharp edge
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block and tackle
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a system of two or more pulleys with a rope or cable threaded between them, usually used to lift or pull heavy loads.
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energy
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the ability to cause change, measured in joules
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potential energy
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energy that is stored due to the interaction between objects
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kinetic energy
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energy a moving object has because of its motion;
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Law of Conservation of Energy
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states that energy cannot be created or destroyed
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temperature
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measure of the average kinetic energy of all the particles that make up an object
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thermal energy
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sum of the kinetic and potential energy of the particles that make up an object
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heat
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energy that is transferred between objects due to a temperature difference between those objects
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conduction
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transfer of thermal energy by collisions between the particles that make up matter
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convection
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transfer of thermal energy in a fluid by the movement of warmer and cooler fluid from one place to another
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radiation
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transfer of energy by electromagnetic waves
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specific heat
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amount of heat needed to raise the temperature of 1kg of a material 1 degrees Celsius
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insulator
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material in which electrons and thermal energy are not able to move easily
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conductor
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material, such as copper wire, through which electrons can move easily
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voltage
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force an electrical current; measure in volts
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resistance
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tendency for a material to oppose electron and to convert electrical energy into other forms of energy; measured in ohms
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electric current
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the net movement of electric charges in a single direction, measured in amperes
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capacitor
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a device used to store an electric charge, consisting of one or more pairs of conductors separated by an insulator
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induction
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the rearrangement of electrons on a neutral object by a nearby charged object
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static electricity
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the accumulation of excess electric charge on an object
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electric circuit
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a closed path that an electric current follows
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parallel circuit
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circuit in which an electric current has more than one path to follow
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series circuit
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circuit in which electric current has only one path to follow
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circuit breaker
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a device that prevents a circuit from overheating and causing a fire; a switch is automatically flipped when the current becomes too great
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fuse
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a small piece of metal that melts if a current becomes to high causing a break in the circuit and stopping the current
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switch
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a device for making and breaking the connection in an electric circuit
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calculate momentum
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momentum p = mass x velocity; [p=mv] example 1: a car with a mass of 1300 kg is traveling south at a speed of 28m/s p = 1300kg x 28m/s; p=36,400kg.m/s south
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calculate potential energy
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gravitational potential energy (J) = mass (kg) x gravity (N/kg) x height (m) [GPE=mgh] example: mass = 4kg; gravity = 9.8N/kg; height = 2.5m GPE = 4kg x 9.8N/kg x 2.5m GPE = 98 N.m or 98J
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calculate kinetic energy
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kinetic energy (in joules) = 1/2 mass (in kg) x [speed (in m/s)]2 [KE = 1/2mv2] mass = 60kg; speed = 3.0m/s KE = 1/2 60kg x( 3m/s)2 1/2 60kg x 9m/s KE = 270J
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calculate force
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Force (net) = mass x acceleration [F=ma] example: mass = .6kg acceleration = 5000m/s2 F = .6kg(5000m/s20 F = 300 kg.ms/s2 F = 300N
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calculate work
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work (in joules) = applied force (in newton) x distance (in meters) [W=Fd] applied force = 100N distance = 5m W = 100N x 5m W = 500J
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solve for weight
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weight (N) = mass (kg) x gravitational strength (N/kg) [Fg = mg] example: mass = 5,000kg gravitational strength = 9.8N/kg Fg = 5000kg x 9.8N/kg Fg(weight) = 49,000N
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solve for acceleration
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acceleration (in meters/second2) = net force (in newtons) divided by mass (kg) [a=F/m] example: mass = 12kg net force = 6N south a = 6Nsouth/12kg a == .5m/s2
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calculate net force
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forces in the same direction are added together; subtract forces in opposite directions; forces NOT in the same direction or in opposite directions cannot be directly added together
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calculate velocity
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velocity is calculated when you take the displacement of an object with its direction and divide it by a change in time
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calculate Ohm's Law
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current (amperes) = voltage difference (volts) / resistance (ohms) [I=V/R] example: voltage difference = 6V resistance = 1,200Ohms I = 6V/1200 Ohms I = .005V/Ohms or .005 A
