According to Newton’s law of gravitation, every particle in the universe attracts every other particle with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centres.
The gravitational force between two bodies of masses m1 and m2 separated by a distance r is:
F ∝ (m1 × m2) / r2
By introducing a constant of proportionality G,
F = G (m1 m2) / r2
The value of gravitational constant is:
G = 6.67 × 10−11 N m2 kg−2
Q1. Newton’s law of gravitation states that force is proportional to: A) m1 + m2 B) m1 − m2 C) m1 × m2 D) m1 / m2 Answer: C Q2. Gravitational force between two bodies is inversely proportional to: A) r B) r² C) r³ D) r⁴ Answer: B Q3. SI unit of gravitational constant G is: A) N kg⁻² B) N m² kg⁻² C) kg m² s⁻² D) N m⁻² Answer: B Q4. If the distance between two masses is doubled, the gravitational force becomes: A) Double B) Half C) One-fourth D) Four times Answer: C Q5. If one mass is doubled and distance remains same, force becomes: A) Half B) Double C) Four times D) One-fourth Answer: B Q6. Value of gravitational constant G is: A) 6.67 × 10⁻¹¹ N m² kg⁻² B) 9.8 m s⁻² C) 3 × 10⁸ m s⁻¹ D) 1.6 × 10⁻¹⁹ C Answer: A Q7. Two masses attract each other with a force of F. If both masses are doubled, the new force will be: A) F B) 2F C) 4F D) F/2 Answer: C Q8. Gravitational force depends on: A) Shape of bodies B) Colour of bodies C) Mass and distance D) Volume only Answer: C
Every particle in the universe attracts every other particle with a force proportional to product of their masses and inversely proportional to square of distance between them.
F = G (m1 m2) / r2
G = 6.67 × 10−11 N m2 kg−2
Numericals are frequently asked using F = G m1 m2 / r2. Pay attention to powers of 10.
