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Learn about Newton’s groundbreaking laws of motion. Explore concepts of inertia, forces, and actions/reactions. Discover demonstrations and resources to deepen your understanding and engage with practical applications.
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Newton’s First Law • "Every body perseveres in its state of being at rest or of moving uniformly straight forward except insofar as it is compelled to change its state by forces impressed." (Principia) • An object in motion will remain in motion and an object at rest will remain at rest unless acted on by an outside force. • Inertia
Newton’s Second Law • "A change in motion is proportional to the motive force impressed and takes place along the straight line in which that force is impressed.” (Principia) • First Part: When I push something, the distance it moves depends on how hard I push it. • Second Part: If I push something, it moves in the direction that I pushed it.
The Most Useful Equation • Newton’s Second Law: (Force = derivative of momentum)
Newton’s Second Law Derived F = ma [F]=[m]*[a] [m]=kg [a]=m/s2 [F]=kg*m/s2=Newton
Special Case: Gravity F = ma FGravity=mg g=9.8 m/s2≈10 m/s2
Newton’s Third Law • "If one object exerts a force on another the other exerts the same force on the one" (Principia) • “For every action there is an equal and opposite reaction!” • ACTION = -REACTION
Newton’s Third Law: Falling FEarth on Bubar= FEB FBubar on Earth= FBE
Newton’s Third Law: Falling Earth on Bubar Bubar on Earth FEB=Fgravity FEB=mBubar*a FEB=mBubar*g FEB=70 kg*10 m/s2 FEB=700 Newtons FBE=FEB=700 N FBE=mE*aE aE=FBE/mE aE=700 N/6E24 kg aE~1E-22 m/s2 FEB = -FBE FEB FBE a Bubar= 10 m/s2 : a Earth=0.0000000000000000000001 m/s2
Hero Engine Fac Fac Fwa Fwa Fwa Fwa Fac Fac
RECALL • Newton’s First Law: Inertia • Newton’s Second Law: F=ma • Newton’s Third Law: Action=-Reaction
Questions? • Lesson, demonstrations and additional resources located online at: http://bubarnewtonslaws.wikispaces.com/ • Your welcome to try demos after class !