Question

6. The distances of two satellites from the surface of the earth are R and 7R. Their time periods of rotation
are in the ratio.
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Answer 1

The ratio of their time period is 1:7

Given data :

Their distance = R and 7R

For simplicity purpose,we assume that the velocity of these two sattelites are equal = x km/hr

So,the distance that has to be covered by,

First sattelite = 2πR

Second sattelite = 2π×7R = 14πR

Now,

First sattelite covers,

x km in = 1 hour

1 km in = 1/x hour

2πR km in = 2πR/x hour

Second sattelite covers,

x km in = 1 hour

1 km in = 1/x hour

14πR km in = 14πR/x hour

So,

Ratio of their time period = 2πR/x ÷ 14πR/x = 2πR/x × x/14πR = 1/7 = 1:7 (answer)