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148 Cards in this Set
- Front
- Back
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the study of matter and energy and the interactions occurring between them
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physics
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person whose teachings dominated scientific thought for 2000 years
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Aristotle
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nation which first studied physics
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ancient Greece
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modern founders of physics
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Galileo and Newton
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scientist who viewed the universe, world, and living things as the special creation of God
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Galileo
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scientist who was perhaps the greatest genius of modern science
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Isaac Newton
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scientist who discovered the laws of motion and gravitation
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Newton
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scientists after Newton who made important contributions to physics
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Robert Boyle, Daniel Bernoulli
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scientists whose work led to making electricity useful and laws of electromagnetism
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Michael Faraday and James Clerk Maxwell
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branches of physics developed before 1900 (includes mechanics, thermodynamics, optics, acoustics, electromagnetism)
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classical physics
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scientist who revolutionized the understanding of motion and gravity
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Albert Einstein
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scientists who studied atoms
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Max Planck, Louis de Broglie, Enrico Fermi
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branches of physics developed since 1900 (includes quantum mechanics, relativity, solid-state physics, particle physics)
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modern physics
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a measurement that includes only magnitude
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scalar quantity
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a measurement that includes both magnitude and direction
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vector quantity
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size or amount
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magnitude
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a scalar representing the length of an object's path
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distance
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an object's change in position (the difference between your starting place and your ending place)
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displacement
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formula for displacement
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or, displacement equals final position minus initial position |
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kind of quantity that displacement is
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vector
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kind of quantity that distance is
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scalar
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method to combine two vectors
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vector addition
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the "answer" in vector addition
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resultant
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shows the combined effect of multiple vectors
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resultant
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vectors that lie in the same or opposite directions
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collinear
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how to solve vectors which are perpendicular to each other
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Pythagorean theorem
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what an object is in as it changes positions
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motion
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study of motion and forces
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dynamics
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study of the effects of forces on matter
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mechanics
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measure of how quickly an object moves
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speed
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formula for speed
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or speed = distance over time |
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the speed of a moving object at one given instant
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instantaneous speed
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speed calculated over a distance
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average speed
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change in position (displacement) over time
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velocity
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formula for velocity
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or, velocity equals displacement divided by time |
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kind of quantity that speed is
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scalar
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kind of quantity that velocity is
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vector
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a change in velocity
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acceleration
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kinds of acceleration
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speed up, slow down, change in direction
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change in velocity per unit of time
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average acceleration
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formula for acceleration
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acceleration (a) = final velocity (vf) – initial velocity (vi) / time (t)
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more specific name for slowing down
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negative acceleration or deceleration
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Newton's famous book about motion
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Principia
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basic topic of Principia
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three laws of motion
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a pushing or pulling of one object on another
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force
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the velocity of an object does not change unless acted upon by an external force
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first law of motion
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objects in motion tend to stay in motion and objects at rest tend to stay at rest unless acted on by an outside force
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first law of motion
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tendency of matter to resist change in motion
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inertia
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another name for first law of motion
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law of inertia
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the force required to accelerate an object at a certain rate equals the object's mass times the desired acceleration
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second law of motion
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formula for second law of motion
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F = ma, or force equals mass times acceleration
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SI unit for force
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newton
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amount of force required to accelerate 1 kg of something at 1 m / s2
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newton
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is force put on an object directly or inversely proportional to its acceleration
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directly
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is force needed to accelerate an object directly or inversely proportional to the object's mass
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directly
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study of objects at rest or in motion at a constant velocity
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statics
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for every action there is an opposite and equal reaction
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third law of motion
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any two objects attract each other through gravitational force
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law of universal gravitation
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formula for gravitational force
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or, gravitation force = gravitational constant times (mass of first object times mass of second object divided by distance squared) |
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G in the gravity formula
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gravitational constant
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the gravitational force exerted on an object near the surface of the earth or another celestial body
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gravity
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first showed that acceleration caused by gravity does not depend on the mass of the object
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Galileo
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to fall with no forces acting except gravity
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free-fall
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the rate a falling object on earth will speed up
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or, 9.81 meters per second squared |
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name for 9.82 m/s2
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acceleration of gravity
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formula that shows how far something can fall in a specific amount of time
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distance = one half times the acceleration of gravity times time squared |
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velocity at which a falling object will stop speeding up
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terminal velocity
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why a falling object stops speeding up
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the force of drag equals the object's weight
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formula for weight
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or, weight = mass times acceleration of gravity |
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force that pulls outward during a circular motion
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centrifugal force
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force that pulls inward during a circular motion
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centripetal force
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force that acts as a centripetal force for the planets (causing them to travel in a circular motion, not straight)
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gravitational force
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resistance to motion caused by a fluid or surface
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friction
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two fundamental causes of friction
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attraction, repulsion
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friction that affects sliding objects already in motion
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kinetic friction
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friction that affects stationary objects, preventing them from moving
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static friction
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friction that affects rolling objects
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rolling friction
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what friction depends on
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the weight of the object and the nature of the surfaces in contact
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the effect of the kind of surfaces as expressed in the equation for friction
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coefficients of friction ()
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equation for kinetic friction
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or, the kinetic friction force = the coefficient of kinetic friction times weight |
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which is usually greater: coefficient of static friction or coefficient of kinetic friction
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coefficient of static friction
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formula for static friction
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or the coefficient of static friction = the coefficient of static friction times weight |
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what Fsf tells you
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the minimum force needed to get an object moving
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the transfer of energy from one object to another by a force
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work
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formula for work
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W = Fd or, work = force times distance
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what is the amount of work done equal to
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the amount of energy transferred
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SI unit for work
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joules (J)
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the work performed by a 1 N force over a distance of 1 m
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1 joule
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the rate of doing work
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power
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formula for power
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or, power = work divided by time |
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is power inversely or directly related to work
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directly
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is power inversely or directly related to time
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inversely
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SI unit of power
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watt
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one joule of work done in one second
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watt (W)
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FPS unit of power
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horsepower
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1 horsepower = ___ watts
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745.7
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the quantity of motion
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momentum
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formula for momentum
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p = mv or, momentum = mass x velocity
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when external forces equal zero, momentum is constant
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law of conservation of momentum
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device for doing work
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machine
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early force-multiplying machines
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simple machines
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three main forms of assistance provided by simple machines
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multiply applied force, multiply distance a force can move something, or change the direction of a force
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force applied to a machine
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input force (Fi)
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the modified force that comes out of a machine
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output force (Fo)
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work put into a machine
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work input
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formula for work input
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or, work input = input force times input distance |
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work obtained from a machine
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work output
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formula for work output
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or, Work output = output force x output distance |
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what is true about work input and work output if no work is lost to friction or other causes
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they are equal
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formula that compares work input and work output
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measure of how much help a machine provides
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mechanical advantage
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mechanical advantage under ideal conditions
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ideal mechanical advantage
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formula for ideal mechanical advantage
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or, ideal mechanical advantage equals input distance over output distance |
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mechanical advantage under non-ideal conditions
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actual mechanical advantage
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formula for actual mechanical advantage
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or, actual mechanical advantage = output force over input force |
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measure of how well a machine converts input work into output work
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efficiency
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formula for efficiency
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or, efficiency = work output over work input |
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simple machine that multiplies force or speed and may or may not change direction
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lever
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a rigid bar or beam resting on a pivot
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lever
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pivot on which a lever's beam rests
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fulcrum
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lever that has the input and output forces on opposite sides of the fulcrum
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class 1 lever (scissors)
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part of the lever from the fulcrum to the input
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input arm
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part of the lever from the fulcrum to the output
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output arm
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advantage of a lever whose input arm is longer than the output arm
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multiplies force
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advantage of a lever whose input arm is shorter than the output arm
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multiplies speed
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lever that has the fulcrum on one end, the input at the other end, and the output between
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class 2 lever (wheelbarrow)
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advantage of a class 2 lever
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multiplies force
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lever that has the fulcrum at one end, the output at the other end, and the input in the middle
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class 3 lever (fly swatter)
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advantage of a class 3 lever
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multiplies distance and speed
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simple machine that has a force applied to rotate a wheel or axle
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wheel and axle
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advantage of a wheel and axle
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multiplies force or speed
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ideal mechanical advantage for a wheel and axle
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or, ideal mechanical advantage = input radius over output radius |
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simple machine made of a rope which passes over a wheel
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pulley
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advantage of a pulley
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multiplies force (or reverses force)
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a pulley that does not move with the load
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fixed pulley
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a pulley that is attached to the moving load
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movable pulley
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a combination of multiple pulleys
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block and tackle
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the pulleys in a block and tackle that multiply force
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the movable pulleys
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the pulleys in a block and tackle that change direction
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the fixed pulleys
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why the block and tackle is a low-efficiency machine
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lots of friction
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a simple machine that consists of a sloping surface
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inclined plane
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ideal mechanical advantage for an inclined plane
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or, ideal mechanical advantage = length over height |
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a special form of inclined plane that directs applied force to the side
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wedge
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ideal mechanical advantage of a wedge
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or, ideal mechanical advantage = length over thickness |
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a simple machine that resembles an inclined plane wrapped around a rod
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screw
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a screw operated as a jack and used to raise very heavy things like houses
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jackscrew
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ideal mechanical advantage of a screw
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or, ideal mechanical advantage = 2 pi radius over pitch |
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the distance from of thread to the next on a screw
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pitch
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