Answer:

Explanation:
speed of bat = 6 m/s
sound wave frequency emitted by bat = 30.0 kHz 
as we know,
speed of sound (c)= 343 m/s



now frequency received by bat is equal to  



hence the frequency hear by bat will be 29.98 Hz
 
        
             
        
        
        
The FFA is the Future Farmers of America. It has no authority in aeronautical matters.
 
        
             
        
        
        
- neon signs
- fireworks
- rockets during the ascent
- meteors
- fireflies
- stars
        
             
        
        
        
The 'formulas' to use are just the definitions of 'power' and 'work':
Power = (work done) / (time to do the work)
and  
Work = (force) x (distance) .
Combine these into one. Take the definition of 'Work', and write it in place of 'work' in the definition of power.
Power = (force x distance) / (time)
From the sheet, we know the power, the distance, and the time.  So we can use this one formula to find the force.
Power = (force x distance) / (time)
Multiply each side by (time):  (Power) x (time) = (force) x (distance)
Divide each side by (distance): Force = (power x time) / (distance).
Look how neat, clean, and simple that is !
Force = (13.3 watts) x (3 seconds) / (4 meters)
Force = (13.3 x 3 / 4) (watt-seconds / meter)
Force = 39.9/4 (joules/meter)
<em>Force = 9.975 Newtons</em>
Is that awesome or what !