Three uniform spheres are located at the corners of an equilateral triangle. Each side of the triangle has a length of 3.10 m. Two of the spheres have a mass of 3.20 kg each. The third sphere (mass unknown) is released from rest. Considering only the gravitational forces that the spheres exert on each other, what is the magnitude of the initial acceleration of the third sphere?

m=3.2 kg, r=3.1 m, m3=M

a=F/m= 2•G•m•M•cos30°/r²•m=
=2•G• M•cos30°/r².

To find the magnitude of the initial acceleration of the third sphere, we need to calculate the gravitational force between the spheres and then use Newton's second law, F = ma, to determine the acceleration.

1. Calculate the gravitational force between each pair of spheres:
The gravitational force between two spheres can be given by Newton's law of universal gravitation:

F = (G * m1 * m2) / r^2

Where:
- F is the gravitational force between the two spheres.
- G is the gravitational constant (approximately 6.67430 x 10^-11 m^3 kg^-1 s^-2).
- m1 and m2 are the masses of the two spheres.
- r is the distance between the centers of the two spheres.

Since the spheres are located at the corners of an equilateral triangle, the distance between the centers of any two spheres is equal to the side length of the triangle. In this case, it is 3.10 m.

Let's calculate the force between the first and third spheres:
F13 = (G * m1 * m3) / r^2

Similarly, calculate the force between the second and third spheres:
F23 = (G * m2 * m3) / r^2

2. Calculate the net force on the third sphere:
The net force on the third sphere is the vector sum of the forces between the spheres.
Fnet = F13 + F23

3. Use Newton's second law to find the acceleration of the third sphere:
Fnet = m3 * a

Rearrange the equation to solve for acceleration:
a = Fnet / m3

Substitute the calculated value of Fnet and the given masses of the spheres into the equation to find the acceleration.

4. Calculate the magnitude of the acceleration:
The magnitude of the acceleration is the absolute value of the acceleration vector. So, take the absolute value of the calculated acceleration.

By following these steps and plugging in the given values, you can find the magnitude of the initial acceleration of the third sphere.