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Announcements:
· Equation Sheet for final (PDF) · Ch. 11: Q: 14,19,20; P: 73,77,84,87,94,100; · Ch. 14: Q: 13,24; P: 76,85,94; · Ch. 15: Q: 12*,13,24; P: 66,67,69,74,79,85; Schedule review session for Wed. Questions on HW. Review test. |
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Announcements:
· HW Ch. 14 Q: 1,2,10; · P:1,2,4,5,6,7,9,14,15,21,23,24,30,33,39; Review and Questions on Ch. 15 Fluids Ch. 14 Gravity: § important on large scales: solar system, galaxies, stars, moon § troubles w/ small scales § very weak but always positive (?) § Newton, Einstein, next? § Newton's Law of gravitation: · magnitude: F = G m_1 m_2 / r^2 · direction: attractive on line between 1 and 2 · G --- Newton's constant 6.67 x 10^-11 Nm^2/kg^2 · Obey's superposition · Example: multiple particles vectors · Example: two particles, where would force be zero? Gravity Near Surface of Earth § F = mg and F = G m_E m / R_E^2 § g = GM_E /R_E^2 Shell Theorems: § Outside: treat spherical mass as point particle at center § Inside: no net force on particle inside spherical dist. Gravitational Potential Energy: § U = \int F dr = -GMm/r § Example: three particles § Potential energy curve: of earth/spaceship § Escape speed v = sqrt{2GM/R} |
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Announcements:
· HW Ch. 15 Q: 1,3,4,5,7,9; · P:1,3,5,8,12,13,23,25,27,29,30,35; Review and Questions on Ch. 11 Rotation Ch. 15 Fluids: § fluids are important § can flow (liquids and gas) § characterized by: · density: rho=m/V · pressure: p = F/A (N/m=Pa) § gauge pressure: difference w/ atmospher Fluids at rest § w/ FBD can derive: · p_2 = p_1 + rho g (y_1-y_2) · p = p_0 + rho g h · p_0 atmospheric pressure § horizontal dimensions doesn't matter § Example: U-tube unknown density Pascal's Principle § change in pressure everywhere (incompressible) § delta p = F_i/A_i = F_o/A_o § Example: hydraulic lever Archimede's Principle § buoyant force: F_b = m_f g § derivation § floating |
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Announcements:
· HW Ch. 11 Q: 4,5,7; · P: 1,2,5,9,11,21,23,29,33,47,50,51,57; Hand Back tests, discuss black number (avg test 3: 62%, avg test avg: 76%, quiz avg: 76, black #: 76) Chapter 11: Rotation § Translation versus Rotation § angular position: theta = s/r § degrees & radians § angular displacement: Delta theta § angular velocity: omega § angular acceleration: alpha § constant angular acceleration equations § relating angular/linear variables: · s = theta * r · v = omega * r · a_t = alpha r · a_r = omega^2 r § Kinetic Energy of rotation K = (1/2) I omega^2 § Moment of Inertia I = Sigma mr^2 § Torque tau = r F sin phi = I alpha |
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Announcements:
· Test next Tuesday; Review Thursday · Hand back quizzes · Equation Sheet for test (PDF) · Ch. 7: Q: 14; P: 41,44,47; · Ch. 8: Q: 12,13,16; P: 69,70,73ab,72,74,79,89 · Ch. 9: Q: 12; P: 61, 63a; Finish Ch. 9 Review Potential Energy Curve Review Energy/Friction problem Newton's Laws for a System Linear Momentum § What it is § units § It's conserved |
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Announcements:
· Test moved to 4/27 · HW Ch. 8 Q: 7,8,9; · P: 36,37,51,54,56,59; · HW Ch. 9 Q: 1; · P: 1,4,5,6,10,21,27,29,31,32; Quiz Reading Potential Energy Curves § turning points § equilibrium (stable & unstable) § F = -dU/dx Including friction in energy problems: fd Ch. 9: Center of Mass |
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Announcements:
· Quiz Thursday · HW Ch. 8 Q: 2,3,4,5; · P: 1,2,3,4,6,9,13,16,19; Potential Energy § Energy inherent in configuration of a system § Examples: gravitational,elastic, chemical § Recognize by the ability of a system to do work § Same units as any other energy § relative: changes in potential significant § change in potential energy is opposite of work done § only associate with conservative forces Path Independence (for conservative forces) Examples: § gravity U(y) = mgy § spring U(y) = 1/2 kx^2 Conservation of Mechanical Energy § picture "before" and "after" § algebraicaly determine E_i and E_f § set equal and solve |
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Announcements:
· HW Ch. 7 Q: 10,13; · P: 21,22,25,31,33,35; Path Invariance of Grav. Work Work done by a variable force Power § P = W/t § P = dW/dt § P = vec F dot vec v § unit: W = J/s Group problems |
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Announcements:
· No class Tuesday · HW Ch. 7 Q: 2,7,8 · P: 1,3,4,7,16,17 Hand back tests; discuss black numbers Energy § hard to define § scalar § many forms § can change forms § defined for system § conserved § unit: J = kg m^2/s^2 Kinetic Energy § energy of motion § 1/2 m v^2 Work § amount of energy transferred § can be positive or negative § W = vec F dot vec d First Energy Theorem: Work-KE Theorem § K_f - K_i = W § Work done by gravity Work done by a Spring § F = - kx § W = \int F dx = 1/2 kx^2 Power § P = W/t § P = dW/dt § P = vec F dot vec v § unit: W = J/s |
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Announcements:
· Omit: 6-3 Drag · May be a bit late to lab tomorrow b/c science fair · HW Ch. 6 Q: 1a, 2,3,4; · P: 1,2,3,37,39 · Equation Sheet for test (PDF) · Ch. 4: Q: 16,22,23; P:69,71,75,81,83,89,90,91; · Ch. 5: Q: 13,15,16,18,19,21*; P:57,58,59*,63,67,71,76; · Ch. 6: P:61-4 Ch. 5 homework questions Friction § friction very complicated; much studied even now § difference with kinetic and static friction: not important to me § magnitude proportional to normal force § direction which opposes motion (don't necessarily need motion) Uniform Circular Motion § centripetal force: force which produces circular motion § direction: towards center of circle § magnitude: mv^2/R |
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Announcements:
· Have a good Spring Break! Hand back and go over Quiz 3 Questions on homework. § Friction problem: guy pulling crate § Newton's Third Law: Equal and Opposite § String and knots problem Group problems |
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Announcements:
· HW Ch. 5 Q: 3,4,5,9,10,12; · P: 3,5,7,11,15,19,27,29,31,33,49,52; · HW Ch. 4 Q: 6,9,11,12,13; · P: 43,45,49, 51; Quiz 3 Relative motion in 1D Ch. 5: Force § Where does acceleration comes from? § Inertial frames of reference § What is mass? § Newton's Laws § Different forces: weight, normal,friction,tension § Newton's Third Law: Equal and Opposite |
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Announcements:
· HW Questions Relative motion in 1D Demo Group problems Quiz |
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Announcements:
· Quiz 3 Thursday · HW Ch. 4 Q: 1,3,4,5; · P: 3,4,6,9,13,17,19,25,29,35,54; Return tests Go over tests, grading method, black numbers, grades Ch. 4 Basics: § x,v,a become vector quantities § vectors become more abstract: different units § horizontal and vertical motion "decouple" Falling ball demo Projectile motion Uniform circular motion § a = v^2/r § T = 2 pi r / v Relative Motion in 1 Dimension |
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Announcements:
· Test Thursday · Equation List for Test 1 (PDF) Return quizzes Review |
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Announcements:
· Quiz Today · Test next Thursday · HW Ch. 3 P: 20, 21, 23, 24 · Ch. 1: P: 31,37,39, 43 · Ch. 2: Q: 10,15; P: 67,72,76,77,78,80,83,85,89 · Ch. 3: P: 40ab,47,48,49,50,51,53 Questions Quiz Review vectors, dot product (perpendicular) Cross product Group problems |
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Announcements:
· Quiz Thursday on Ch. 2 · HW Ch. 3 Q: 9,10 · P: 29,31,37 Questions Vectors: § Representations of a vector: mag/dir,x/y,i/j § Practical issues: degree & radians, inverse trig functions § Coordinate freedom: adding two vectors § Multiplying vectors |
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Announcements:
· HW Ch. 3 Q: 1 · P: 1,3,5,7,11,13,19 Questions Last question of group problems Return quizzes Vectors: § Why do we need them? § Combine at least two bits of info § Can be written in different ways § How to add/subtract vectors? |
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Announcements:
· HW Ch. 2 Q: 5,7,8 · P: 22,24,25,27,33,35,40,42,45,49 Questions Quiz Group Problems from Ch. 2 |
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Announcements:
· HW Ch. 1 P: 1,3,4,5,7,10,15,21 · Ch. 2 Q: 1-4, P:1,3,5,7,11,17,20 · First Quiz Tuesday (units,math,scientific notation) Math review: algebra, geometry, trig, derivatives Density Ch. 2 § Describe motion, don't worry about why § Position, speed, velocity, and acceleration § Graphs |
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Announcements:
· First day of class Take roll. Handout syllabus What is physics? |