We are given with
distance traveled through vacuum = 1.0 m
refractive index of water = 1.33
refractive index of glass = 1.50
refractive index of diamond = 2.42
distance traveled through water is = 1.0/1.33 = 0.75 m
distance traveled through water is = 1.0/1.50 = 0.67 m
distance traveled through water is = 1.0/2.42 = 0.41 m
        
                    
             
        
        
        
Answer: 996m/s
Explanation:
Formula for calculating velocity of wave in a stretched string is
V = √T/M where;
V is the velocity of wave
T is tension 
M is the mass per unit length of the wire(m/L)
Since the second wire is twice as far apart as the first, it will be L2 = 2L1
Let V1 and V2 be the speed of the shorter and longer wire respectively
V1 = √T/M1... 1
V2 = √T/M2... 2
Since V1 = 249m/s, M1 = m/L1 M2 = m/L2 = m/2L1
The equations will now become 
249 = √T/(m/L1) ... 3
V2 = √T/(m/2L1)... 4
From 3,
249² = TL1/m...5
From 4,
V2²= 2TL1/m... 6
Dividing equation 5 by 6 we have;
249²/V2² = TL1/m×m/2TL1
{249/V2}² = 1/2
249/V2 = (1/2)²
249/V2 = 1/4
V2 = 249×4
V2 = 996m/s
Therefore the speed of the wave on the longer wire is 996m/s
 
        
             
        
        
        
Vocabulary should be, I think: 
I. Hypothesis 
II. Evidence, data
III. Experiment
What is your question exactly? 
        
                    
             
        
        
        
Answer:
The entropy of a gas increases when it expands into a vacuum because the number of possible states increases . 
Explanation:
When a gas expand in a vacuum, the molecules of the gases vibrates very fast and starting moving with higher velocity in random directions which means the level of disorder in the gases increases. 
Now the possible state of the gas molecule increases such as the particle can be located at different position due to increased randomness. 
<u>Entropy is the measure of this randomness and thus with this increased randomness entropy also increases.</u>
 
        
             
        
        
        
Because 'acceleration' does NOT mean 'speeding up'.  
It means ANY change in motion ... speeding up, slowing down, 
or changing DIRECTION.
When traveling a roundabout, or any curved path, the direction
is constantly changing even if the speed is constant, so there is 
constant acceleration going on.