There is no image? Maybe put an image in next time so we know what to solve
Answer:
-1
Explanation:
The coefficient of y in the equation x+y=40 is 1. To make the y-terms cancel when the second equation is added, its coefficient must be -1. It has a coefficient of 1 now, so that equation should be multiplied by -1.
(x +y) +(-1)(y) = (40) +(-1)(0)
x = 40 . . . . . . . simplified; y-terms were cancelled
This is called, The Doppler effect.
In short terms, when the trains is farther away the wavelength of the whistles sound are longer and more separate from each other, and more farther away from you, as it gets closer to you, the wavelengths start getting shorter and more louder the closer it gets to you. Basically the <span>wavelengths change because of the motion of the source.</span>
Explanation:
Formula to calculate angular acceleration is as follows.
or, 
Putting the given values into the above formula as follows.
= 
= 0.326 
Thus, we can conclude that the wheel’s angular acceleration if its initial angular speed is 2.5 rad/s is 0.326 .
