AIEEE 2009 Solved Paper

Given that, at height h from ground the acceleration due to gravity becomes ‌

g

9

.
We know acceleration at earth surface due to gravity g=‌

GM

R2

and acceleration at height h due to gravity g′=‌

GM

(R+h)2

So ‌

g

9

=‌

GM

(R+h)2

⇒‌

g

9

=‌

GM

R2

⋅‌

R2

(R+h)2

=g⋅(‌

R

R+h

)2
⇒‌

1

9

=(‌

R

R+h

)2
⇒‌

R

R+h

=‌

1

3

⇒3R=R+h
∴h=2R