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7.Gravitation
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પૃથ્વીની સપાટીથી ....... $km$ ઊંચાઈએ " $g$ " નું મૂલ્ય $2\%$ જેટલું ઘટશે ? [પૃથ્વીની ત્રિજ્યા $6400\,km$ ]
A
$32$
B
$64$
C
$128$
D
$1600$
Solution
(b)
Acceleration due to gravity above the surface of earth at a height $h$ is given $g^{\prime}=g\left(1-\frac{2 h}{R_\theta}\right)$ here, $g^{\prime}=0.98 \,g$
$\Rightarrow 0.98=1-\frac{2 h}{R_e}$
$\Rightarrow \frac{2 h}{R_e}=0.02$
$h=0.01 R_e$
$=0.01 \times 6400 \,km$
$=64 \,km$
Standard 11
Physics
