Question

The magnitude of gravitational potential energy of three particles, each of mass 6 mg placed on vertices of an equilateral triangle of edge length 1 m is:-

(A)7.8 10-15 J
(B) 7.2 x 10-21 J
(C)4.96 x 10-4 J
(D)8.1 10-13 J​

Answer 1

Answer:

May be the answer is (B)

Answer 2

Given:

Mass of each particle = 6 mg

Edge length of the equilateral triangle = 1 m

To find:

The magnitude of gravitational potential energy.

Solution:

Gravitational potential energy of one pair of two particle = -Gm²/ l

3 pairs can be formed like this, therefore the gravitational potential energy = 3Gm²/l

Here m= 6 mg = 6*10⁻⁶ kg

Gravitational potential energy = 3*6.7*10⁻¹¹*(6*10⁻⁶)² / 1 = 723.6* 10⁻²³

=7.2*10⁻²¹ J

Therefore the gravitational potential energy is 7.2*10⁻²¹ J, Option B is correct.