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Discuss and apply Newton’s laws (i.e., first, second, third, and law of universal gravitation)
- first - a body continues in a state of rest or uniform motion unless acted upon by a net force
- second - F= m a
- third - if body A exerts a force F on body B, then body B exerts an equal but oppositely directed force F on body A
- law of universal gravitation - F = G m1 (m2)/r2
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Define pressure and relate it to fluid flow and buoyancy (e.g., heart valves, atmospheric pressure)
- pressure = F/A
- atmospheric pressure - the pressure exerted by the Earth's atmosphere on the surface of the Earth
- blood pressure - heart must generate enough pressure to pump blood through the arteries and to the lungs and body
- heart valves - prevent back flow
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Describe the relationships among position, distance, displacement, speed, velocity, acceleration, and time, and perform simple calculations using these variables for both linear and circular motion
- position - point or area it occupies in space
- distance - how much ground is covered, has magnitude but no direction
- displacement - change in position, difference between an object's final and initial position, Delta s
- speed - change in position of the object over time, speed of a point mass
- velocity - vector quantity that has direction, the rate of change of position
- acceleration - the change in a velocity vector in a corresponding change in time
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Identify the separate forces that act on a body (e.g., gravity, pressure, tension/compression, normal force, friction) and describe the net force on the body
- normal force: acts perpendicularly out from the surface of the object that is exerting it
- tension: the force of a rope or string that is pulling on an object
- compression: result of a force applied to the outside of an object that pushes inward or acts to reduce the size or volume of an object
- friction: ubiquitous, direction of the force is always opposite to the direction of motion
- pressure: the pressure of a fluid on a body that is submerged in that fluid acts normal to the surface of the body
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Construct and analyze simple vector and graphical representations of motion and forces (e.g., distance, speed, time)
- can use graph to find position of the object at any time
- velocity of the object can be found from the slope of the graph
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Identify fundamental forces, including gravity, nuclear forces, and electromagnetic forces (magnetic and electric), and explain their roles in nature, such as the role of gravity in maintaining the structure of the universe
- gravity: dominant force in the universe, shapes the structures in the universe
- electromagnetic force: holds atoms and molecules together, a force between charged particles or magnetic poles
- strong nuclear force: holds the nucleus of an atom together and is involved in nuclear fission and fusion
- weak nuclear force: involved in radioactive decay, can act on many types of particles
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Explain and calculate mechanical advantages for levers, pulleys, and inclined planes
- W = F x d
- simple machines do not reduce the amount of work required, they spread out the required force over a larger distance
- MA = distance over which effort applier moves/ distance over which the load moves
- lever - effectiveness depends on the forces of the load and effort on the distances of these forces from the fulcrum
- pulley - reduces effort, must pull rope greater distance
- inclined plane - easier to move up or down, must move the object over a greater distance
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