Has an Environmental Impact. Perhaps the largest disadvantage of hydroelectric energy is the impact it can have on the environment.
It Displaces People.
It's Expensive.
There are Limited Reservoirs.
There are Droughts.
It's Not Always Safe
Answer:
The value is 
Explanation:
From the question we are told
The pipe diameter at location 1 is 
The velocity at location 1 is 
The diameter at location 2 is 
Generally the area at location 1 is

=> 
=> 
=> 
Generally the area at location 1 is

=> 
=> 
Generally from continuity equation we have that

=> 
=> 
=> 
Answer:
The correct answer is d Both the observer's are correct
Explanation:
We know by postulates of relativity that laws of physics are same in different inertial frames.
Thus for each of the frames they make observations related to their frames and since the observations are true for their individual frames they both are correct. But when we compare the two frames we need to use transformation equations to compare both the results.
i thinkits an instrument called seismograph. not sure