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32 Cards in this Set
- Front
- Back
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Machines
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multiplies force by reducing distance
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work input =
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work output
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Simple lever F * D=
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F * D
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Work energy Theorem
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"The work done on an object is equal to the energy gained by the object"
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Efficiency
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useful energy output/ total energy input
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Momentum
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momentum= mass * velocity
Because velocity is a vector quantity, so is momentum. Changes in velocity cause change in momentum |
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Newton's 1st Law
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momentum does not change unless acted on by an outside force
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Acceleration
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When velocity changes, this is by definition acceleration.
Acceleration = Change in velocity/ Change in time |
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Newtons 2nd Law
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acceleration= force/mass
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Impulse
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Force * time, The greater the impulse, the greater the change in velocity
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Notes units of Newton
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kg/ (m * sec2)
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Work Energy Theorem
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The work done on an object is equal to the energy gained by the object.
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efficiency
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useful energy output/ total energy input
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TANSTAAFL =
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There aint no such thing as a free lunch"
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Rotational Intertia
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Newton's 1st law applied to rotating objects
"An object rotating about an axis tends to remain rotating around that same axis unless acted on by an outside torque." |
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Pendulum or hoop
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I= m * r (2) (squared)
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Cylinder
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I= (1/2) *m * r (2)
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Torque
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lever arm * force
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Center of mass
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also called center of gravity
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stability
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center of mass must be over the a point of support
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centripetal force
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towards center of circular path
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centrifugal force
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tangent to circular path
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Angular momentum
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rotational inertia * rotational velocity
for special case of large r compared with size of object Angular momentum= m *v*r |
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Kepler's Laws of Planetary Motion
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1. Each planet moves in an elliptical orbi with the sun at one focus of the ellipse.
2. The line from the sun to any planet sweeps out equal areas of space in equal intervals of time 3. If the period ( the time it takes for a planet to make a complete cycle or orbit around the sun) is denoted T, and the average distance from teh sun is denoted R, Then for any planet T(squared) - R (cubed) |
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Newton's law of Universal Gravitation
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An object in orbit around the sun or Earth is affected by two vector forces- the momentum of the object (directed along the tangent to the orbit) and the force of gravity (directed along the line between the center of mass of the object and Earth's center of mass
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F = m(1) *m(2) / d(2)
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F = distance bewteen the centers of m(1) and m(2)
m = mass |
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newtons law of universal gravitation
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is an inverse square law
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sun - earth - moon alignment= full moon
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= highest tide
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sun- moon-earth alignment= new moon
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= lowest tide
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Movement of ionosphere induces
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magnetic field, affects cosmic radiation
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Black Holes
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IF a burnt out star collapses to a small enough volume, gravitational force on light may make escape velocity greater than the speed of light
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Escape velocity
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how fast an object has to be moving to break free of gravity
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