Ultrasound was used to check for cracks in an aeroplane wing. The ultrasound pulse would be reflected from any cracks and from the end of the wing. The diagram shows the oscilloscope trace produced by the echo. How far along the wing was the crack? The speed of sound in metal is 5000 M/S.

Which is not a source of noise pollution? a)airplanes b)acid rain c)machines d)cars

Aparticle travels in a circular orbit of radius 21 m. its speed is changing at a rate of 23.1 m/s2 at an instant when its speed is 37.2 m/s. what is the magnitude of the acceleration (in m/s? ) of the particle?

One day, after pulling down your window shade, you notice that sunlight is passing through a pinhole in the shade and making a small patch of light on the far wall. you see that the patch of light seems to be a circular diffraction pattern. it appears that the central maximum is about 1 cm across and you estimate that the distance from the window shade to the wall is about 3 m. what is (a) the average wavelength of sunlight? (b) the diameter of the pinhole?