Yasir

Author: yasir

  • Temperature

    —

    by

    yasir
    in

    Temperature is one of the seven SI base quantities. Physicists measure temperature on the Kelvin scale, which is marked in units called kelvins. Although the temperature of a body apparently has no upper limit, it does have a lower limit; this limiting low temperature is taken as the zero of the Kelvin temperature scale. Room temperature is about 290…

  • Temperature, Heat, and the First Law of Thermodynamics

    —

    by

    yasir
    in

    How can a dead rattlesnake strike a reaching hand? The answer is in this lesson. Because of their highly poisonous venom, rattlesnakes pose a danger to humans. When the snakes are discovered in residential areas, they are usually killed. However, the death of a rattlesnake does not immediately decrease its danger. Indeed, numerous people have…

  • Supersonic Speeds, Shock Waves

    —

    by

    yasir
    in

    If a source is moving toward a stationary detector at a speed equal to the speed of sound—that is, if νS = ν—Eqs. 17-47 and 17-55 predict that the detected frequency f′ will be infinitely great. This means that the source is moving so fast that it keeps pace with its own spherical wavefronts, as Fig. 17-23a suggests. What happens when the speed of…

  • The Doppler Effect

    —

    by

    yasir
    in

    A police car is parked by the side of the highway, sounding its 1000 Hz siren. If you are also parked by the highway, you will hear that same frequency. However, if there is relative motion between you and the police car, either toward or away from each other, you will hear a different frequency.…

  • Beats

    —

    by

    yasir
    in

    If we listen, a few minutes apart, to two sounds whose frequencies are, say, 552 and 564 Hz, most of us cannot tell one from the other. However, if the sounds reach our ears simultaneously, what we hear is a sound whose frequency is 558 Hz, the average of the two combining frequencies. We also hear a…

  • Sources of Musical Sound

    —

    by

    yasir
    in

    Musical sounds can be set up by oscillating strings (guitar, piano, violin), membranes (kettledrum, snare drum), air columns (flute, oboe, pipe organ, and the horns of Fig. 17-13), wooden blocks or steel bars (marimba, xylophone), and many other oscillating bodies. Most instruments involve more than a single oscillating part. In the violin, for example, both the…

  • Intensity and Sound Level

    —

    by

    yasir
    in

    If you have ever tried to sleep while someone played loud music nearby, you are well aware that there is more to sound than frequency, wavelength, and speed. There is also intensity. The intensity I of a sound wave at a surface is the average rate per unit area at which energy is transferred by the wave through…

  • Interference

    —

    by

    yasir
    in

    Like transverse waves, sound waves can undergo interference. Let us consider, in particular, the interference between two identical sound waves traveling in the same direction. Figure 17-8 shows how we can set up such a situation: Two point sources S1 and S2 emit sound waves that are in phase and of identical wavelength λ. Thus, the sources themselves are said to…

  • Traveling Sound Waves

    —

    by

    yasir
    in

    Here we examine the displacements and pressure variations associated with a sinusoidal sound wave traveling through air. Figure 17-5a displays such a wave traveling rightward through a long air-filled tube. Recall from Lesson 16 that we can produce such a wave by sinusoidally moving a piston at the left end of the tube (as in Fig. 16-2). The piston’s rightward…

  • The Speed of Sound

    —

    by

    yasir
    in

    The speed of any mechanical wave, transverse or longitudinal, depends on both an inertial property of the medium (to store kinetic energy) and an elastic property of the medium (to store potential energy). Thus, we can generalize Eq. 16-26, which gives the speed of a transverse wave along a stretched string, by writing where (for transverse…