The next step is -748 divide by -11 is 68 m (answer) the pic got cropped sorry
Send wave from your location to the object and wait until echo is back.
Measure the time taken.
If you know the speed of wave (say sound wave), than just multiply by half time taken wave to return
Answer:
option B
Explanation:
given,
Satellite B has an orbital radius nine times that of satellite A.
R' = 9 R
now, orbital velocity of the satellite A
........(1)
now, orbital velocity of satellite B
from equation 1
hence, the correct answer is option B
g Generally the accepted value of acceleration due to gravity is 9.801 
as per the question the acceleration due to gravity is found to be 9.42
in an experiment performed.
the difference between the ideal and observed value is 0.381.
hence the error is -
=3.88735 percent
the error is not so high,so it can be accepted.
now we have to know why this occurs-the equation of time period of the simple pendulum is give as-![T=2\pi\sqrt[2]{l/g}](https://tex.z-dn.net/?f=T%3D2%5Cpi%5Csqrt%5B2%5D%7Bl%2Fg%7D)

As the experiment is done under air resistance,so it will affect to the time period.hence the time period will be more which in turn decreases the value of g.
if this experiment is done in a environment of zero air resistance,we will get the value of g which must be approximately equal to 9.801 
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i think so ,but i am not sure</span>