# Shared Flashcard Set

## Details

Physics
review for midterm
61
Physics
Professional
07/24/2013

Term
 inertia
Definition
 sluggishness or apparent resistance of an object to change its stat of motions. mass is the measure of inertia
Term
 Newtons 2nd Law of Motion
Definition
 force is equal to mass times acceleration (laymen s terms). The acceleration produced by a net force on an object is directly proportional to the magnitude of the net force, is in the same direction as the net force, and is inversely proportional to the mass of the object
Term
 Newtons 1st Law of Motion
Definition
 An object at rest remains at rest or it if is in motion it moves with uniform velocity until it is acted on by a resultant force (also known as the law of inertia)
Term
 Newtons 3rd Law of Motion
Definition
 for every action there is an equal and opposite reaction
Term
 force
Definition
 any influence that tends to accelerate an object; a push or a pull measured in Newtons. Force is a vector quantity
Term
 net force
Definition
 combination of all the forces that act on an object
Term
 Equilibrium rule
Definition
 EF = 0. On an object or system of objects in mechanical equilibrium, the sum of forces equals zero.
Term
 speed
Definition
 how fast something moves; the distance an object travels per unit of time; the magnitude of velocity.
Term
 velocity
Definition
 speed of an object and its direction of motion; a vector quanity
Term
 vector quantity
Definition
 quantity in physics that has both magnitude and direction. exm, force , velocity, acceleration, torque and electric and magnetic fields
Term
 scalar quantity
Definition
 in physics, such as mass, volume, and time that can be completely specified by its magnitude and has no direction
Term
 acceleration
Definition
 rate at which an object's velocity changes with time/ acceleration = change of velocity/(divided) time interval
Term
 friction
Definition
 force that acts to resist the relative motion of objects or materials that are in contact
Term
 mass
Definition
 quantity of matter in an object (form of energy)
Term
 weight
Definition
 the force that an object exerts on a supporting surface
Term
 pressure
Definition
 force per surface area where the force is normal to the surface; measured in pascals
Term
 Buoyant force
Definition
 net upward force exerted by a fluid on a submerged or immersed object
Term
 archimedes Principle (liquid and gas)
Definition
 Relationship between buoyancy and displaced fluid. an immersed object is buoyed up by a force equal to the weight of the fluid it displaces.
Term
 principle of floatation
Definition
 a floating object displaces a weight of fluid equal to its own weight.
Term
 pascal's principle
Definition
 changes in pressure at any point in an enclosed fluid at rest are transmitted undiminished to all points in the fluid and act in all directions
Term
 atmospheric pressure
Definition
 pressure exerted against bodies immersed in the atmosphere resulting from the weight of air pressing down from above
Term
 Boyle's Law
Definition
 the product of pressure and volume os a constant for a given mass of confined gas regardless of changes in either pressure of volume individually, as long as temperature remains unchanged
Term
 Bernoulli's principle
Definition
 pressure in a fluid along a given streamline decreases as the speed of the fluid increases.
Term
 temperature
Definition
 measure of the average translational kinetic energy per molecule of a substance, measured in Celsius or Fahrenheit or in kelvins
Term
 absolute zero
Definition
 lowest possible temperature that any substance can have
Term
 heat
Definition
 the energy that flows from on object to another by virtue of a difference in temperature; measured in calories or joules
Term
 internal energy
Definition
 the total energy stored in the atoms and molecules within a substance. changes in internal energy are of principal concern in thermodynamics
Term
 specific heat capacity
Definition
 quantity of heat required to raise the temperature of a unit mass of a substance by 1 degree Celsius, often simply called specific heat
Term
 conduction
Definition
 In heat, energy transfer from particle to particle within certain materials, or from one material to another when the two are in direct contact. (B) in electricity, the flow of electric charge through a conductor
Term
 convection
Definition
 Means of heat transfer by movement of the heated substance itself, such as by currents in a fluid
Term
Definition
 a) energy transmitted by electromagnetic waves. b) the particles given off by radioactive atoms such as uranium. do not confuse radiation with radioactivity.
Term
 Newtons Law of cooling
Definition
 the reate of cooling of an object whether by conduction, convection,k or radiation, is approximately proportional to the temperature difference between the object and its surroundings
Term
 Greenhouse effect
Definition
 warming effect caused by short-wave-length radiant energy from the Sun that easily enters the atmosphere and is absorbed by Earth, but when radiated at longer wavelengths cannot easily escape Earth's atmosphere
Term
 Evaporation
Definition
 change of phase from liquid to gas that takes place at the surface of a liquid ; the opposite of condensation
Term
 sublimation
Definition
 direct conversion of a substance form the solid to the vapor phase without passing through the liquid phase
Term
 condensation
Definition
 change of phase of gas into a liquid ; the opposite of evaporation
Term
 regelation
Definition
 process of melting under pressure and the subsequent refreezing when the pressure is removed
Term
 latent heat of fusion
Definition
 the amount of energy required to change a unit mass of a substance form solid to liquid
Term
 latent heat of vaporization
Definition
 the amount of energy required to change a unit mass of a substance form liquid to gas
Term
 thermodynamics
Definition
 study of heat and its transformation to mechanical energy, characterized by two principal laws
Term
 1st law of thermodynamics
Definition
 a restaement of the law of conservation of energy as it applies to systems involving changed in temperature; whenever heat is added to a system , it transforms to an equal amount of some other form of energy
Term
 2nd law of thermodynamics
Definition
 heat cannot be transferred form a colder body to a hotter body without work being done by an outside agent
Term
 entropy
Definition
 a measure of the disorder of a system. whenever energy freely transforms from one form to another, the direction of transformation is toward a state of greater disorder and therefore toward a state of greater disorder and therefore toward on of greater entropy
Term
 What is the net force on a cart that is pulled to the right with 100 pounds and to the left with 30 pounds?
Definition
 Net force is 70 pounds to the right.
Term
 why do we say that force is a vector quantity
Definition
 to know the complete value of a force we must know its magnitude and direction. anything that has the magnitude and direction is given the name vector.
Term
 can force be expressed in units of pounds and also in units of newtons
Definition
 yes
Term
 what is the net force on an object that is pulled with 80 newtons to the right and 80 newtons to the left?
Definition
 0
Term
 what is the net force on a bag pulled down by gravity with 18 newtons and pulled upward by a rope with 18 newtons
Definition
 0
Term
 what does it mean to say something is in mechanical equilibrium?
Definition
 the sum of all the forces on it are zero and therefore can not accelerate
Term
 State the equilibrium rule in symbol notation
Definition
 EF= 0
Term
 consider the book that weighs 15N at rest on a flat table. how many newtons of support force does the table provide? what is the net force on the book in this case?
Definition
 the table provide a equal force of 15N b)Because it is at rest, it is 0
Term
 when you stand at rest on a bathroom scale, how does your weight compare with the support force by the scale?
Definition
 they have equal magnitudes, the support force shows your weight
Term
 a bowling ball at rest is in equilibrium. Is the ball in equilibrium when it moves at constant speed in a straight-line path?
Definition
 yes
Term
 What is the test for whether or not a moving object is in equilibrium?
Definition
 If an object is not acceleration it is in equilibrium.
Term
 If you push on a crate with a force of 100N and it slides at constant velocity, how much is the friction acting on the crate?
Definition
 Also 100N , in the opposite direction, making the net force 0
Term
 what two units of measurement are necessary for describing speed?
Definition
 distance and time
Term
 what kind of speed is registered by an automobile speedometer-average speed or instantaneous speed?
Definition
 instantaneous
Term
 distinguish between instantaneous speed and average speed.
Definition
 instantaneous is at a particular moment where as average is over some time.
Term
 what is the average speed in kilometers per hour for a horse that gallops a distance of 15 km in a time of 30min?
Definition
 average speed= total distance covered/time interval. 15/.5=30kmph
Term
 how far does a horse travel if it gallops at an average speed of 25km/h for 30 min.
Definition
 speed x time = distance 25x.5=12.5
Term
 distinguish between speed and velocity
Definition
 speed is the rate on which an object changes position. velocity is the speed and direction of an object.
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