progressive wave

progressive wave, physics

1. PROGRESSIVE WAVES PRESENTER: SITI AMIRA BT ABDULLAH (DEHS) NUR ASHIKIN BINTI CHE ALIAS ( DEHS) NUR SHAHIRAH BINTI ZOLKIFLI ( DEHS) NIK NUR FARHANA BINTI NIK MOHAMAD ( DBLT)

2. SUMMARY a)DEFINITION b)PARAMETERS c)EQUATIONS d)EXAMPLE QUESTION

3. DEFINITIONS ~ Progressive waves  distribute energy from a point source to a surrounding area. They move energy in the form of vibrating particles or fields. ~ Two types of progressive waves:

4. TRANSVERSE WAVES: The waves propagates in the direction perpendicular to t he direction of vibration of particles. The waves propagates in the form of crests and troughs. Example of transverse waves: vibration of a string, light, water.

5. LONGITUDINAL WAVES: The waves propagates in the direction parallel to the direction of vibration of particles. The waves propagates as compressions and rarefactions. Example of longitudinal waves: sound waves and earthquake waves.

6. WAVES PARAMETERS: 1) AMPLITUDE, A The maximum displacement of the vibrating particle from the equilibrium position. S.I unit: m

7. 2) PERIOD, T The time taken to complete one full cycle S.I unit: s

8. 3 ) FREQUENCY, f The number of cycle per unit time, f=1/T S.I unit: or Hz  

9. 4 ) ANGULAR FREQUENCY, Ѡ Ѡ = = 2 S.I unit:       Time, s position

10. 5 ) WAVE LENGTH, λ The length along the direction of propagation between two corresponding point at the same phase. S.I unit: m

11. 6 ) WAVE NUMBER, k k= S.I unit: rad  

12. 7 ) PHASE A and B = in phase B and C = in anti phase Phase difference = φ Calculating φ for x1 and x2 φ = ( x1- x2)  

13. THE WAVE EQUATIONS Wave moving in +x axis (forward) direction y(x, t) = A sin ( ω t- kx + φ ) Or y( x,t ) = A sin ( kx - ω t+ φ ) Waves moving in x-axis (backward) direction. y( x,t ) = A sin ( ω t+ kx + φ ) Or y( x,t ) = A sin ( kx + ω t + φ ) Note: A = amplitude, ω = angular frequency, k= wave number, φ = phase angle.

14. VELOCITY OF PARTICLES VELOCITY OF PROPAGATION The distance per unit time made by wave as it propagates in the medium. v= f λ Propagation velocity dependent on medium in which the waves propagates. Velocity in stretched string v= where T = tension, μ =mass density= mass/ length  

15. GRAPHICAL REPRESENTATION OF WAVES Displacement – time graph (y-t) y (x , t) = A sin ( ω t – kx )

16. Displacement – distance graph (y-x) y (x , t) = A sin ( ω t – kx )

17. EXAMPLE QUESTION The question of progressive wave is given as y = 0.3 sin (5 ) Where x and y is in meter and t is in seconds. Determine its amplitude, frequency, wavelength, velocity, and wave direction. Answer: y = O.3 sin (5 ) y = A sin ( kx – ωt ) 1) amplitude (A) = 0.3 m Angular frequency ( ω ) = 200 Wave number (k) = 5 2) Wavelength, λ k= 5 5 λ = λ = 0.4m  

18. 3 ) Angular frequency ( ω ) = ω = 200 200 T= T= 0.01 s 5) wave direction= backward (-x-axis) frequency, f= f = f= f= 100 Hz 4) Velocity v=f λ f= 100 Hz λ = 0.4m v= 100 = 100   The end