You are driving at 25 m/s when an ambulance passes you and pulls into your lane, just in front of you, and speeds ahead at 35 m/s. The ambulance driver hears a siren sound of 850 Hz. What frequency do you hear

The value is  

Explanation:

From the question we are told that

    The speed is

     The speed of the ambulance is

     The frequency of the siren is  

Generally from Doppler effect equation we have that

Here is the velocity of sound with the value  

  =>  

  =>  

concave lenses are used here. they spread the light out before it reaches the convex lens in the eye, therefore letting the image focus directly on the retina. hyperopia is known to you probably as farsightedness.