Question

A surfer is on the wave sinusoidal in shape with crests 14. The surfer bobs vertical distance 3.6 m from trough to crests in 1.5 s. Find the wave speed. Write down the expressions for the particle's displacement and its speed. A police has a frequency of 550 Hz as it approaches you, 450 Hz after it has passed. How fast is the police car traveling? Sand speed 343 m/s. A light ray is aimed at 1 cm thick glass at an angle 30 degree the glass. Index of refraction for glass is 1.5. What is the ray's direction of travels in glass? What is the speed in the glass if c = 3 times 10^8 m/s. A pencil is placed 70 cm from 5 cm focal length of converging camera lens. Draw ray tracing diagram Describe the image What is the distance of the image? What is its magnification?

Answer 1

Q.2. Case 1

$\large 550 Hz = \frac{v}{v-v_{s}}f$

Case 2

$\large 450 Hz = \frac{v}{v+v_{s}}f$

Dividing equation 1 by 2 we get

$\large \frac{450 Hz}{550 Hz} = \frac{v-v_{s}}{v+v_{s}}$

$\large \frac{9}{11} = \frac{v-v_{s}}{v+v_{s}}$

$\large 9(v+v_{s}) = 11(v-v_{s})$

$\large 9v_{s}+11 v_{s} = 11v-9v$

$\large v_{s} = \frac{2v}{20} = 0.1 \times 343 m/s = 34.3 m/s$

Q.3. Direction is towards the normal.

$\large r = \sin^{-1}(\frac{\sin 30^{0}}{1.5})= 19.5^{0}$

Speed of light in glass is

$\large v= \frac{3\times 10^{8}m/s}{1.5} = 2\times 10^{8}m/s$