I would say B surface tension
        
                    
             
        
        
        
Answer:
Explanation:
distance of fan A = 18.3 m
distance of fan B = 127 m 
speed of sound (s) = 343 m/s
 What is the time difference between hearing the sound at the two locations?
time (T) = distance / speed
- time for sound to reach fan A = 18.3 / 343 = 0.053 s
- time it takes for sound to reach fan B = 127 / 343 = 0.370 s
- time difference = 0.370 - 0.053 = 0.317 s
 
        
             
        
        
        
Wee can use here kinematics
as we know that

for shorter tree we know that


now since we know that other tree is twice high 
So height of other tree is y = 39.2 m
now again by above equation



so the time taken is 2.83 s
 
        
             
        
        
        
Explanation:
1 inch = 25.4 mm
1 foot = 12 inches
1 mile = 5260 feet
1 cm = 0.01 m or 10 mm
Now Sammy's height is 5 feet and 5.3 inches.
(a) We need to find Sammy's height in inches. 
Since, 1 foot = 12 inches
5 feet = 5 × 12 inches = 60 inches
Now, 5 feet and 5.3 inches = 60 inches + 5.3 inches = 65.3 inches
Sammy's height is 65.3 inches.
(b) We need to find Sammy's height in feet.
Since, 1 foot = 12 inches

So,

5 feet and 5.3 inches = 5 feet + 0.4416 feet = 5.44 feet
Sammy's height is 5.44 feet.