470 likes | 620 Views
Laws of Motion Classical Mechanics. A brief overview. Aristotle (384 - 322 BC). Natural Motion All objects have internal homing instincts similar to those observed in animals. Galileo (1564 - 1642). Law of Falling Bodies All bodies fall with a constant acceleration
E N D
Laws of MotionClassical Mechanics A brief overview
Aristotle (384 - 322 BC) Natural Motion All objects have internal homing instincts similar to those observed in animals
Galileo (1564 - 1642) Law of Falling Bodies All bodies fall with a constant acceleration under gravity regardless of mass
Kepler (1571 - 1630) Laws of Planetary Motion Planetary orbits are elliptical
Isaac Newton (1643 - 1727) 1661: Entered Trinity College, Cambridge 1665: Received his Bachelor’s Degree. University closed due to Plague. Re-opened 1667. 1668: Awarded Masters degree
W = m x g • W = weight (N) • m = mass (kg) • g = acceleration due to gravity (m/s2 ) Acceleration due to gravity of falling body on Earth (excluding effects of air resistance) is, on average, 9.8 m/s2 This value is often rounded off to 10 m/s2
1669 - 1687 Lucasian Professor of Mathematics (Cambridge)
Newton’s Scientific Achievements • Law of Universal Gravitation • Laws of Motion • Advances in Optics - studies of colour & light • Constructed the first reflecting telescope in 1668 • Calculus
Newton’s 1st Law • An object that is at rest will stay at rest until an unbalanced force acts upon it. • An object that is in motion will not change its velocity until an unbalanced force acts upon it.
Newton’s 2nd Law • A body will accelerate with acceleration proportional to the force and inversely proportional to the mass F = m x a • F = Net Force (N) • m = mass (kg) • a = acceleration (m/s2 )
Momentum p = m x v • p = momentum (kg.m/s) or (N.s) • m = mass (kg) • v = velocity (m/s)
Momentum • Can be defined mathematically. • Is a vector because it has magnitude as well as direction. • When bodies collide, momentum is transferred. • In any collision, momentum is conserved.
Law of Conservation of Momentum The total momentum of a system is the same before a collision as after. m1u1 + m2u2 = m1v1 + m2v2
Impulse • Is defined as the change in momentum experienced by a body. Δ p = m x Δ v Δ p = F x Δ t
Newton’s 3rd Law • Every action has a reaction equal in magnitude and opposite in direction
Some weblinks …. • Crash Test Results • http://www.youtube.com/watch?v=zmUBgTHppv8 • NASA movie ‘Orville and Wilbur Wright’ Newton’s Laws and Flight • http://www.grc.nasa.gov/WWW/K-12/airplane/newton.html • Space Shuttle launches • http://www.youtube.com/watch?v=4FROxZ5i67k • http://www.youtube.com/watch?v=iwfsFtpACFw&feature=related • NASA Apollo 11 Mission • http://www.youtube.com/watch?v=LNm1LVJTJ2k&feature=related • http://www.youtube.com/watch?v=wdSPF7ujsdw&feature=related • NASA TV • http://www.youtube.com/NASATelevision