Answers:
a) 
b) 
Explanation:
a) The centripetal acceleration  of an object moving in a uniform circular motion is given by the following equation:
 of an object moving in a uniform circular motion is given by the following equation:  
 
  
Where:
 is the angular velocity of the ball
 is the angular velocity of the ball
 is the radius of the circular motion, which is equal to the length of the string
 is the radius of the circular motion, which is equal to the length of the string
Then:
 
  
 This is the centripetal acceleration of the ball
 This is the centripetal acceleration of the ball
b) On the other hand, in this circular motion there is a force (centripetal force  ) that is directed towards the center and is equal to the tension (
) that is directed towards the center and is equal to the tension ( ) in the string:
) in the string:

Where  is the mass of the ball
 is the mass of the ball
Hence:

 This is the tension in the string
 This is the tension in the string
 
        
             
        
        
        
If it takes 

 seconds to reach the car, then the distance 

 is 

.
The bear's distance from the tourist's starting point is

For maximum 

, we set the equations equal to each other:



so the distance is
 
 
        
        
        
Length of the pipe = 0.39 m
Third harmonic frequency = 1400 Hz
For the third harmonic:
Wavelength = 
The center of the open pipe will host a node and the nearest anti - node from the center will be at the 0.25 × wavelength
Distance from center  = 0.25 × wavelength
Distance = 
Plugging the value of the length of the pipe (L) = 0.39 m = 39 cm
Distance = 
Distance from the center to the nearest anti - node = 6.5 cm
Hence, the nearest distance to the anti - node from the center = 6.5 cm
So, option C is correct.
 
        
             
        
        
        
Explanation:
It is given that,
Bandwidth of a laser source, 
(b) Let t is the time separation of sections of sections of the light wave that can still interfere. The time period is given by :



(a) Let h is the coherence length of the source. It is given by :

c is the speed of light

l = 0.0099 m
Hence, this is the required solution.