# Shared Flashcard Set

## Details

Science Semester Test
Prentice Hall Physical Science (Concepts in Action)
112
Physics
05/18/2015

## Additional Physics Flashcards

Term
 frame of reference
Definition
 system of objects that are not moving with respect to one another
Term
 Relative motion
Definition
 movement in relation to a frame of reference
Term
 distance
Definition
 length of a path between two points
Term
 vector
Definition
 quantity that has magnitude and direction
Term
 resultant vector
Definition
 vector sum of two or more vectors
Term
 displacement
Definition
 is the direction from the starting point and the length of a straight line from the starting point to the end point
Term
 what is needed to describe motion accuratly and completely?
Definition
 a frame of reference
Term
 how do you add displacements?
Definition
Term
 speed
Definition
 ratio of the distance an object moves to the amount of time the object moves
Term
 instantaneous speed
Definition
 the rate at which an object is moving at a given moment in time
Term
 average speed
Definition
 the total distance traveled divided by the time it takes to travel that distance
Term
 velocity
Definition
 the speed and direction in which an object is moving
Term
 how are instantaneous speed and average speed different?
Definition
 average speed is computed for the entire duration of a trip, and instantaneous speed is measured at a particular instant
Term
 how can you find the speed from a distance-time graph?
Definition
 the slope of a line on a distance-time graph is speed
Term
 how are speed and velocity different?
Definition
 velocity is the description of both speed and direction of motion. velocity is a vector
Term
 how do velocities add?
Definition
 two or more velocities add by vector addition
Term
 acceleration
Definition
 rate at which velocity changes
Term
 free fall
Definition
 the movement of an object toward earth solely because of gravity
Term
 constant acceleration
Definition
 steady change in velocity
Term
 linear graph
Definition
 a graph in which the displayed data form a straight line
Term
 nonlinear graph
Definition
 a graph in which the displayed data form a curved line
Term
 how are changes in velocity described?
Definition
 acceleration can be described as changes in speed, changes in direction, or changes in both. Acceleration is a vector
Term
 how can you calculate acceleration?
Definition
 you calculate acceleration for straight-line motion by dividing the change in velocity by the total time
Term
 how does a speed-time graph indicate acceleration?
Definition
 the slope of a speed-time graph is acceleration
Term
 what is instantaneous acceleration?
Definition
 instantaneous acceleration is how fast a velocity is changing at a specific instant
Term
 force
Definition
 push or pull that acts on an object
Term
 newton
Definition
 force that causes 1-kilogram mass to accelerate at a rate of 1 meter per second each second
Term
 net force
Definition
 overall force acting on an objectafter all the forces are combined
Term
 friction
Definition
 force that opposes the motion of objects that touch as they move past each other
Term
 static friction
Definition
 friction force that acts on objects that are not moving
Term
 sliding friction
Definition
 force that opposes the direction of motion of an object as it slides over a surface
Term
 rolling friction
Definition
 friction force that acts on rolling objects
Term
 fluid pressure
Definition
 opposes the motion of an object through a liquid
Term
 air resistance
Definition
 fluid friction acting on an object moving through the eye
Term
 gravity
Definition
 is a force that acts between any two objects
Term
 terminal velocity
Definition
 constant velocity of a falling object when the force of air resistance equals the force of gravity
Term
 projectile motion
Definition
 the motion of a falling object after it is given an initial forward velocity
Term
 how do forces affect the motion of an object?
Definition
 a force can cause a resting object to move, or it can accelerate a moving object by changing the object's speed or direction
Term
 what are the four main types of friction?
Definition
 there are four main types of friction: static friction, sliding friction, rolling friction, and fluid friction
Term
 how do gravity and air resistance affect a falling object?
Definition
 gravity causes objects to accelerate downward, whereas air resistance acts in the direction opposite to the motion and reduces acceleration
Term
 in what direction does earths gravity act?
Definition
 earth's gravity acts downward toward the center of earth
Term
 why does a projectile follow a curved path?
Definition
 the combination of an initial forward velocity and the downward vertical force of gravity causes the ball to follow a curved path
Term
 inertia
Definition
 tendency of an object to resist a change in its motion
Term
 mass
Definition
 measure of the inertia of an object and depends on the amount of matter the object contains
Term
 weight
Definition
 force of gravity acting on an object
Term
 how does Newton's first law relate change in motion to a zero net force?
Definition
 according to newton's first law of motion, the state of motion of an object doesn't change as long as the net force acting on the object is zero. inertia
Term
 how does Newton's second law relate force, mass, and acceleration?
Definition
 according to newton's second law of motion, the acceleration of an object is equal to the net force acting on it divided by the object's mass
Term
 how are weight and mass related?
Definition
 mass is a measure of the inertia of an object; weight is a measure of the force of gravity acting on an object
Term
 momentum
Definition
 product of an object's mass and its velocity
Term
 law of conservation of momentum
Definition
 if no net force acts on a system, them the total momentum of the system does not change
Term
 what is newton's third law of motion?
Definition
 according to newton's third law of motion, whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first object
Term
 what is needed for an object to have a large momentum?
Definition
 an object has a large momentum if the product of its mass and velocity is large
Term
 how is momentum conserved?
Definition
 in a closed system, the loss of momentum of one object equals the gain in momentum of another object- the momentum is conserved
Term
 what force can attract and repel?
Definition
 electric force and magnetic force are the only forces that can both attract and repel
Term
 what force holds the nucleus together?
Definition
 two forces, the strong nuclear force and the weak nuclear force, act within the nucleus to hold it together
Term
 what is newton's law of universal gravitation?
Definition
 newton's law of universal gravitation states that every object in the universe attracts every other object
Term
 pressure
Definition
 the result of a force distributed over an area
Term
 pascal
Definition
 SI unit of pressure
Term
 fluid
Definition
 a substance that assumes the shape of its container
Term
 how is pressure calculated?
Definition
 divide the force by the area over which the force acts
Term
 how does water pressure change with depth?
Definition
 water pressure increases as depth increases.
Term
 how is pressure distributed at a given level in a fluid?
Definition
 the pressure in a fluid at any given depth is constant, and it is exerted equally in all directions
Term
 How does air pressure change with altitude?
Definition
 air pressure decreases as the altitude increases
Term
 hydraulic system
Definition
 device that uses pressurized fluid acting on pistons of different sizes to change a force
Term
 lift
Definition
 the pressure difference between the top and bottom of the wing creates an upward force
Term
 how does Pascal's principle describe the transmission of pressure through a fluid?
Definition
 a change in pressure at any point in the fluid is transmitted equally and unchanged in all directions throughout the fluid
Term
 how does a hydraulic system work?
Definition
 an increased output force is produced because a constant fluid pressure is exerted on the larger area of the output piston
Term
 how does the speed of a fluid related to the pressure within the fluid?
Definition
 according to Bernoulli's principle, as the speed of a fluid increases, the pressure within the fluid decreases
Term
 buoyancy
Definition
 abitlity of a fluid to exert an upward force on an object placed in it
Term
 buoyant force
Definition
 upward force that acts in the opposite direction of gravity
Term
 archimedes' principle
Definition
 the buoyant force on an object is equal to the weight of the fluid displaced by the object
Term
 what is the effect of buoyancy on the apparent weight of an object?
Definition
 Buoyancy results in the apparent loss of weight of an object in a fluid
Term
 how can you determine if an object will float or sink in a fluid?
Definition
 if an object is less dense than the fluid it is in, it will float. If te object is more dense than the fluid is, it will sink
Term
 work
Definition
 product of force and distance
Term
 joule
Definition
 the SI unit of work
Term
 power
Definition
 rate of doing work
Term
 watt
Definition
 SI unit of power
Term
 horsepower
Definition
 equal to 746 watts
Term
 when does a force do work?
Definition
 for a force to do work on an object, some of the force must act in the same direction as the object moves. If there is no movement, no work is done.
Term
 how are work and power related?
Definition
 any part of a force that does not act in the direction of motion does no work on an object
Term
 machine
Definition
 device that changes a force
Term
 input force
Definition
 force you exert on a machine
Term
 input distance
Definition
 the distance the input force acts through
Term
 work input
Definition
 the work done by the input force acting through the input distance
Term
 output force
Definition
 the force that is exerted by a machine
Term
 output distance
Definition
 the distance the output force is exerted
Term
 work output
Definition
 output force multiplied by the output distance
Term
 how do machines make work easier?
Definition
 machines make work easier to do. They change the size of a force needed, the direction of a force, or the distance over which a force acts
Term
 how are work input and work output related for a machine?
Definition
 because of friction, the work done by a machine is always less than the work done on the machine
Term
Definition
 the mechanical advantage of a machine is the number of times that the machine increases an input force
Term
Definition
 the mechanical advantage determined by measuring the actual forces acting on a machine
Term
Definition
 ima of a machine is the mechanical advantage in the adsence of friction
Term
 efficiency
Definition
 percentage of the work input that becomes work output
Term
 how does actual mechanical advantage of a machine compare to its ideal mechanical advantage?
Definition
 Because of friction, is always present, the actual mechanical advantage of a machine is always less than the ideal mechanical advantage
Term
 why is efficiency of a machine always less than 100%?
Definition
 because there is always some friction, the efficiency of any machine is always less than 100%
Term
 lever
Definition
 a rigid bar that is free to move around a fixed point
Term
 fulcrum
Definition
 the fixed point the bar rotates around
Term
 input arm
Definition
 the input arm of a lever is the distance between the input force and the fulcrum
Term
 output arm
Definition
 is the distance between the output force and the fulcrum
Term
 wheel and axle
Definition
 simple machine that consists of two disks or cylinders, each one with a different radius
Term
 inclined plane
Definition
 a slanted surface along which a force moves an object to a different elevation
Term
 wedge
Definition
 v-shaped object whose sides are two inclined planes sloped toward each other
Term
 screw
Definition
 an inclined plane wrapped around a cylinder
Term
 pulley
Definition
 simple machine that consists of a rope that fits into a groove in a wheel
Term
 compound machine
Definition
 combination of two or more simple machines that operate together
Term
 what are the six types of simple machines?
Definition
 lever, wheel and axle, inclined plane, wedge, screw, and pulley
Term
 what determines the mechanical advantage of the lever?
Definition
 to calculate the IMA of any lever, divide the input arm by the output arm
Term
 what determines the mechanical advantage of the wheel and axle?
Definition
 to calculate the IMA of the wheel and axle, divide the radius where the input force is exerted by the radius where the output force is exerted
Term
 what determines the mechanical advantage of the inclined plane?
Definition
 the IMA of an inclined plane is the distance along the inclined plane divided by its change in height
Term
 what determines the mechanical advantage of the wedge?
Definition
 a thin wedge of a given length has a greater IMA than a thick wedge of the same length
Term
 what determines the mechanical advantage of the screw?
Definition
 screws with threads closer together have a greater IMA
Term
 what determines the mechanical advantage of the pulley?
Definition
 the IMA of a pulley or pulley system is equal to the number of rope sections supporting the load being lifted
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