(23. In Young's double slit experiment, total 63 fringes are seen in visible region for sodium light of wavelength \( 5893 \AA \). If violet light of wavelength \( 4358 \AA \) is used in place of sodium light, then total number of fringes seen will be \( n \). Find \( n \).

3.33 • Uma canoa tem velocidade de \( 0,40 \mathrm{~m} / \mathrm{s} \) a sudeste em relação à Terra. A canoa se desloca em um rio que escoa a \( 0,50 \mathrm{~m} / \mathrm{s} \) para leste em relação à Terra. Determine o módulo, a direção e o sentido da velocidade da canoa em relação ao rio.

Train moving with speed of \( (40 \mathrm{~m} / \mathrm{s}) \) the driver have resorted to the use of brakes to reduce the speed of the train movement by rate \( \left(-2 \mathrm{~m} / \mathrm{s}^{2}\right) \) Calculate: a) The amount of time it takes for the train even stops completely. b) The amount of distance traveled since the train began braking until it stops

Example 10 Three coplanar forces of magnitudes \( F, 5,3 \) Newton act on a particle and the measure of the angle between the second the third force is \( 60^{\circ} \). Find the value of \( F \) if the forces are in equilibrium.

(c) When the temperature reaches \( -18^{\circ} \mathrm{C} \), the pressure of the gas in the cylinder is still equal to that of the atmosphere. Explain, in terms of the particles of the gas, how the pressure remains equal to its original value. Explain, in terms of the particles of the metal, why the decrease in the volume of the metal is less than that of the gas. decrease in the volume of the metal is much less than the decrease in the volume of the gas.

27. Two trains, 1 and 2 , have an equal mass of \( m=5,000 \mathrm{~kg} \) each. Train 1 is traveling with a speed \( n=15 \mathrm{~m} / \mathrm{s} \) before striking train 2 , which was at rest. If the two trains lock together as the result of the collision. What is their common speed immediately after collision?