Question

Two objects attract each other with a gravitational force of ${10}^{-8}N$, when separated by 20 cm. If their total mass is 5 kg,the mass of the objects in kg , are

• A. 4, 1
• B. 3 , 2
• C. 2.5 , 2.5
• D. 3.5 , 1.5

Answer 1

The correct option is B 3 , 2

Let the mass of one object be x kg.

Then mass of second object = (5-x) Kg

Also, distance between objects = 20cm = $0.2m$

We know that,

$F=\frac{G{m}_1{m}_2}{r^2}$

${10}^{-8}=\frac{6.6\times {10}^{-11}\times x\times (5-x)}{(0.2{)}^2}$

Solving we get,

$\sim x^2-5x+6=0$

$⟹x=3,2$

Hence, the correct answer is B.