U1 Physics for Engineering (main topics).pptx

The following material represents a little class for all those engineers who need to learn basic physics. Hope these may be helpful for everyone who needs it.

1. Physics for engineering

2. Acoustics branch of physics that studies sound

3. Periodic motion ( or movement ) It is one in which a body moves from one side to another in a fixed trajectory, returning to each position and speed, after a defined interval of time. A wheel of fortune The turn of a disk The rotation of fan blades Rotation and translation movement of the Earth

4. Simple harmonic motion ( or movement ) Due to a restoring force whose magnitude is directly proportional to the distance of the object from an equilibrium position and acts towards the equilibrium position. It results in an oscillation that is described by a sinusoid which continues indefinitely (if uninhibited by friction or any other dissipation of energy).

5. Period Time it takes to complete a cycle of the wave (seconds, minutes, hours, years, months, days) Frequency Number of times per second in which a complete cycle of a wave is completed 1 cycle / seg = 1 Hertz (Hz)

6. Main F o rmulas 𝑇 = 1 𝐹 𝐹 = 1 𝑇 T = perio d F = frecu ency

7. Definition and parts of a wave Crest It is the highest point of the wave Valley It is the lowest point of the wave

8. Definition and parts of a wave Node It is the point where the wave crosses the equilibrium line. Elongation It is the distance between any point on a wave and its equilibrium position.

9. Definition and parts of a wave wave amplitude It is the maximum elongation that a wave reaches

10. wave phenomena Reflection It occurs when a wave propagates and when colliding with the material medium it returns in the same direction but in the opposite direction.

11. wave phenomena Refraction It occurs when the wave propagates from one medium to another of different density.

12. wave phenomena Interference It occurs when two or more waves exist simultaneously in the same medium.

13. Overlap When several waves meet and are added. wave phenomena

14. Ex 1 The musical note has a frequency, by international convention, of 440 Hz. If in the air it propagates with a speed of 340 m/s and in the water it does so at 1400 m/s, calculate its wavelength in those media

15. Ev 1 1) What wavelength is the note “A” on a 440 Hz tuning fork? ( Vsound = 340 m/s) 2) If the period of a vibrating movement is 10 seconds, the frequency will be: 0.1 Hz? 100 Hz? 3) If a body vibrates at a rate of 100 cycles per second, what is the total period? 4) The period of a vibrating movement is 0.02 s. What is its frequency? How many vibrations occur in 2 minutes? 5) A sound wave, with a wavelength of 1.7 m, propagates in air with a speed of 340 m/s. What is the value of your period and its frequency?

16. Ev 1 6) With what speed does a wave of wavelength 40 m and frequency 3000 Hz propagate? 7) A vibrating movement with a frequency of 100 Hz is transmitted at a speed of 72 km/h. What is the wavelength of this vibratory motion? 8) The lower and upper frequencies of audible sounds are, respectively, 20 Hz and 20,000 Hz. Calculate the wavelengths corresponding to these frequencies. 9) A disturbance transmitted in the form of waves along a string takes 8 s to travel 12 m, producing 8 complete oscillations. Calculate: a) The speed of wave propagation. b) The wavelength. c) The frequency of the wave. 10) The string of a guitar vibrates with a frequency of 435 Hz. What is the wavelength of the sound produced? What would be the length of this sound in water?