Question

three uniform spheres each of mass m and radius r are placed in contact on a straight line. Find net force of gravitation on second sphere. 1

Answer 1

Answer:

Each of the spheres can be assumed to be masses located at the center of the sphere of mass m. Hence the three spheres will constitute three particles each of mass m located at vertices of equilateral triangle of side 2r. Force on each mass due to the other sphere will be

Due to the sphere F

1

=

(2r)

2

Gm

2

Due to second sphere F

2

=

(2r)

2

Gm

2

Note that F

1

and F

2

will be oriented along two side of the equilateral triangle at an angle of 60

0

.

Resultant force on each sphere

F

1

=

F1

2

+F2

2

+2F1F2cos60

0

F

1

=

3

4r

2

Gm

2

Is it correct

Answer 2

Answer:

0

Explanation:

the force by first sphere on second cancels out the force by third on first