
To find the value of α, we are given the relation:
F₁ / F₂ = 2 / √α
A 1 kg mass is placed at the center of a square, and masses are placed at the four corners of the square. The gravitational force acting on the central mass due to each corner mass acts along the line joining that corner to the center.
Step 1: Force due to a single corner mass
The gravitational force between two masses separated by a distance r is:
F = G × m₁ × m₂ / r²
Here, the distance r from each corner to the center is the same for all masses. Thus, the magnitude of force due to each corner mass is directly proportional to the mass placed at that corner.
Step 2: Calculation of F₁
In the first arrangement, the masses at the corners are:
4m, 3m, m, and 2m
The forces due to these masses act along different directions, and the net force on the central mass is obtained by vector addition of these individual forces.
Step 3: Calculation of F₂
In the second arrangement, the masses 4m and 3m are interchanged.
Since the distances remain unchanged, only the directions of the forces associated with these two masses are swapped, which alters the resultant force on the central mass.
Step 4: Ratio of forces
Using symmetry and vector addition of forces for both configurations, the ratio of the magnitudes of the resultant forces is given as:
F₁ / F₂ = 2 / √α
Comparing the numerical values obtained from the vector sums, this condition is satisfied when:
α = 5
Final Answer:
α = 5
Net gravitational force at the center of a square is found to be \( F_1 \) when four particles having masses \( M, 2M, 3M \) and \( 4M \) are placed at the four corners of the square as shown in figure, and it is \( F_2 \) when the positions of \( 3M \) and \( 4M \) are interchanged. The ratio \( \dfrac{F_1}{F_2} = \dfrac{\alpha}{\sqrt{5}} \). The value of \( \alpha \) is 
