Question

Under which of these conditions can you conclude with certainty that the total momentum before a collision is the same as after the collision?

A. Gravity is the only force acting on the system.
B. The forces that each object in a system exerts on the other in any pair of objects are equal in size and opposite in direction.
C. There are external net forces but the objects in the system exert no forces on each other.
D. The system of objects has no forces from outside the system acting on it.

Answer 1

what do you think?

Answer 2

we can demonstrate that it is the option B, for a system composed by N particles interacting each other. Nevertheless the computation is long

Answer 3

ohh okay!! so our solution is choice B?

Answer 4

that's right!

Answer 5

yay!! thank you:)

Answer 6

please wait a moment

Answer 7

okay!

Answer 8

on our system no external force has to act, namely there aren't external forces, which are acting on our system

Answer 9

so I think it is option D

Answer 10

ohh so it would not be choice B?

Answer 11

ahh okay!! :)

Answer 12

ok!! :)