Answer:
<u>The asteroid was not detected until it was extremely close to Earth. </u>
Explanation:
According to data from NASA, the Asteroid named 'Astriod 2019 OK', was detected when it was extremely close to earth with just about an estimated distance of 73,000 kilometers (45,000 miles) from the Earth.
Scientists were concerned at the proximity of this space object to the Earth before it was discovered, and it brought about a cause of concern that since it was not extremely large (estimated 57 to 130 meters wide) it creates a potential for other smaller asteroids to escape detection and struck the earth.
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Answer:
The frequency is
Explanation:
From the question we are told that
The frequency of the tuning fork is 
The beat period is 
Generally the beat frequency is mathematically represented as


The beat frequency is also represented mathematically as

Where
is the frequency of the piano
So
<span>Answer:
Using 1/f = 1/d' + 1/d ...(where d' object distance and d is image distance)
1/4 = 1/7 + 1/d
1/4 - 1/7 = 1/d
3/28 = 1/d
d = 28/3
d = 9.33 cm</span>