College Physics II Physics 1402 Second Class

1
College Physics II - Physics 1402Second Class

• E M Conceptual Survey Results
• Mechanics Transition
• SHM
• Simple Pendulum
• Forced and Damped Oscillations
• Lab Activity

2
Mechanics TransitionSimple Harmonic Motion

• Displacement of an object undergoing SHM
• x(t) xm sin (wt f) (in m)
• Amplitude xm
• Angular frequency w
• w 2 p / T 2 p f
• Phase angle or constant f
• Graphing
• Velocity of an object undergoing SHM
• v(t) w xm cos (wt f) (in m/s)
• Amplitude maximum velocity w xm
• Examples

3
Mechanics TransitionSimple Harmonic Motion II

• Acceleration of an object undergoing SHM
• a(t) - w2 xm sin (wt f) (in m/s2)
• Amplitude maximum acceleration w2 xm
• Notice that a(t) - w2 x(t)
• Examples
• Horizontally Vibrating Spring
• Force due to SHM
• F m a m - w2 x(t) (in N)
• Period T

4
Mechanics TransitionSimple Harmonic Motion III

• Horizontally Vibrating Spring (continued)
• Graphs and examples
• Figure 1.5
• Force and Energy
• Elastic Potential Energy
• Us 1/2 ks x2m sin2 (wt f) (in Nm or J)
• Kinetic Energy
• K 1/2 ks x2m cos2 (wt f) (in Nm or J)
• Examples
• Table 1

5
Simple Pendulum

• Using Force and Motion ideas
• q l
• m
• Period is
• Examples

6
Forced and Damped Oscillations

• Damping force
• Fd - b v
• Angular frequency
• Forced oscillations
• Examples

7
Sinusoidal Waves - Sine Wave

• x(t) A sin (wt f)
• x (m)
• 1
• t (s)
• 0 p/2 p 3p/2
  2p
• -1
• 0 90 180
  270 360
• 0 T/4 T/2
  3T/4 T
• For this example, A 1
• w 1 w 2 p/T T 2 p/1 2 p
• f 0

8
Sinusoidal Waves - Cosine Wave

• x(t) A cos (wt f)
• x (m)
• 1
• t (s)
• 0 p/2 p 3p/2
  2p
• -1
• 0 90 180
  270 360
• 0 T/4 T/2
  3T/4 T
• For this example, A 1
• w 1 w 2 p/T T 2 p/1 2 p
• f 0

9
Next Class

• Work on SHM Homework
• Start Coverage of Mechanical Waves
• Introduction to Waves Lab
• Turn in Periodic Motion Lab and Homework