Question

The mass of the earth is 6 × 1024 kg and that of the moon is 7.4 1022 kg. If the distance between the earth and the moon is 3.84105 km, calculate the force exerted by the earth on the moon. G = 6.7 10–11 N m2 kg-2.

NCERT Class IX
Sciences - Main Course Book

Chapter 10. Gravitation

Answer 1

m1 = 6 * 10^24 kg
m2 = 7.4 * 10^22 kg

d = 3.84 * 10^5 km

Gravitational force =  G m1 m2 / d^2
       F = 6.7 * 10^-11  *    6 * 10^24  *  7.4 * 10^22 / (3.84 * 10^5)^2
          = 2 * 10^26  Newtons

Answer 2

Answer:

2 × 10³⁰ N

Explanation:

Given :

Mass of earth = 6 × 10²⁴ kg

Mass of moon = 7.4 × 10²² kg

Distance between them = 3.84105 km = 3.84105 × 10³ m

We have value of G = 6.7 × 10⁻¹¹ N m² kg⁻²

We have to find force :

We have :

F = G m₁ m₂ / r²

F = ( 6.7 × 10⁻¹¹ ) ( 6 × 10²⁴ ) ( 7.4 × 10²² ) / (  3.84105 × 10³ )² N

F = 2 × 10³⁰ N

Hence force exerted by the earth on the moon is 2 × 10³⁰ N.