Question

The mass of a ball is four times the mah% another ball. When these balls are separated 13,1 a distance of 10 cm, the gravitational fum between them is $6.67\times {10}^{-7}N$. Then the mass the each ball in Kg is

• A. $0.5,2$
• B. $50,20$
• C. $2,5$
• D. $20$

Answer 1

The correct option is D $20$

According to Newton's law of gravitation, force is directly proportional to product of masses and inversely proportional to square of separation between masses.here, G is gravitational constant.

, r = 10cm = 0.1m

and F = 6.67 × 10^-7 N

we know, G = 6.67 × 10^-11 Nm²/kg²

so, F = G/r²

or, 6.67 × 10^-7 = 6.67 × 10^-11× 4 × ²/(0.1)²

or, 10⁴ = 4²/0.01

or, ² = 25

or, = 5 kg

and then, = 4 × 5 = 20kg