JEE Main202124 Feb 2021Morning ShiftPhysicsGravitationActual
Four identical particles of equal masses 1 kg made to move along the circumference of a circle of radius 1 m under the action of their own mutual gravitational attraction. The speed of each particle will be:
Options
- AG 1 + 2 2
- BG 2 1 + 2 2
- CG 2 2 2 - 1
- D1 + 2 2 G 2
Correct answer
D. 1 + 2 2 G 2
Step-by-step solution
F 1 = G m m 2 R 2 = G m 2 4 R 2   F 2 = G m m 2 R 2 = G m 2 2 R 2   F 3 = G m m 2 R 2 = G m 2 2 R 2 ⇒ F net = F 1 + F 2 cos 45 ° + F 3 cos 45 ° = G m 2 4 R 2 + G m 2 2 R 2 1 2 + G m 2 2 R 2 1 2 = G m 2 R 2 1 4 + 1 2 = G m 2 4 R 2 1 + 2 2 F net = G m 2 4 R 2 1 + 2 2 = m v 2 R ⇒ v = G 1 + 2 2 2