A train passes by a little boy at the depot. As it moves away from the boy at 65
m/s, the whistle emits a frequency of 4500hz.
What frequency does the little boy hear as
the train barrels off into the distance? The speed
of sound in air is 343m/s

Determine the change in width a, height b, thickness t when a plate is subjected to the uniform distributed load and is made of material having modulus of elasticity e=230 gpa and poisson's ratio ν=1/3. given : a=400 mm and b= 300 mm also the uniformly distributed load in downward y direction of plate is 2 mn/m and in the positive x direction is 3 mn/m and t=20 mm