The last days Today –Review N7-N10 test, begin review for the final Thursday – Open lab, Work on any unfinished lab or problems Friday – Review (energy problems using CPS. Monday – review Tuesday – Open lab Wednesday – 7:00 – 10:00 Final Exam - All work and extra credit due.

N7-N10 test results 90 – students 80 – 897 students 70 – 795 students 55 – 694 students Overall average in the class 90 – students 80 – 8913 students 70 – 795 students 55 – 693 students Students in this range have a very good possibility of receiving an “A” in the class Most probable grade is a “B” Most probable grade is “C” The above estimates are based on past experience. Past experience has also shown that students can move from one of these groups to another.

Chapter N11 Oscillatory Motion

Hooke’s law The force an ideal spring exerts on an object at position x. The second derivative of the position with respect to time. A differential equation. A constant that tells how stiff the spring is. The solution to the differential equation. This gives the position of the object as a function of time. – The equation of motion. The mass of the object attached to the spring. Phase angle

Sinusoidal Waves Amplitude of the wave Phase rate ω = angular frequency = 2πf f = frequency = number of waves per second f = frequency Period = T = 1/f = time between wave crests passing a given point.

Simple harmonic motion

Phase Angle These two oscillations have the same frequency and period but differ by a phase angle of 50º. 50º

A 1 kg weight hung on a spring causes the spring to stretch 30 cm. If the weight is hung on the spring, then pulled down 5 cm and released, what is the equation of motion of the weight? Step 1, find the spring constant. F = -kx F = 9.8 N, x = 0.3 m k = F/x = 32.7 N/m y = y 0 Cos(ωt) = 0.05 Cos(5.72t)

Problems for Friday N11B1, B2, B3, S1

The last days Today – chapter N11, our last new chapter Tomorrow – Ballistic pendulum lab Wed –begin review for the final Thursday – Open lab, Work on any unfinished lab or problems Friday – Review Monday – review Tuesday – Open lab Wednesday – Final Exam

The last days Today –Review N7-N10 test, begin review for the final Thursday – Open lab, Work on any unfinished lab or problems Friday – Review (energy problems using CPS. Monday – review Tuesday – Open lab Wednesday – 7:00 – 10:00 Final Exam - All work and extra credit due.