An artillery shells is moving on a parabolic trayectory, when it explodes in midair. The shell chatters into a very large number of fragments. Which of the following statements is true? (Select all that apply.)

A) A center of mass of the system of fragments will contitnue to move on the initial parabolic trayectory until the last fragment touches the ground.
B) The force of the explosion is an internal force and thus cannot alter the total momentum of the system.
C)The force of the explosion will decrease the momentum of the system of fragments, and so the momentum of the shell is not conserved during explosion.
D) The center of mass of the system of fragments will continue to move on the parabolic trayectory until first fragment touches the ground.
E) The center of mass of the system of fragments will have the trayectory that depends of the number of fragments and their velocities right after the explosion.
F) None of the above.

I thought it was A and B but I was not right...

B and D. As soon as the first fragnent hits the ground, external forces are applied to the system of fragments.

The total momentum of the system is continually altered by gravity, but not by the explosion.

Thanks!!

To determine which statements are true, let's evaluate each option:

A) According to the law of conservation of momentum, the center of mass of the system of fragments will continue to move on the initial parabolic trajectory until the last fragment touches the ground. This is because, in the absence of external forces, the total momentum of the system remains constant.

B) The force of the explosion is indeed an internal force. Internal forces do not affect the total momentum of a system. Therefore, the total momentum of the system of fragments will remain unchanged.

C) This statement is incorrect. The force of the explosion may increase or decrease the momentum of the system, but the total momentum of the system will remain constant due to the law of conservation of momentum.

D) This statement is incorrect. As mentioned earlier, the center of mass of the system of fragments will continue to move on the initial parabolic trajectory until the last fragment touches the ground.

E) This statement is correct. The trajectory of the center of mass of the system of fragments will depend on the number of fragments and their velocities immediately after the explosion. The distribution of mass and velocity among the fragments will determine the subsequent motion of the center of mass.

Considering the evaluation of each statement, the correct answers are:

A) A center of mass of the system of fragments will continue to move on the initial parabolic trajectory until the last fragment touches the ground.
B) The force of the explosion is an internal force and thus cannot alter the total momentum of the system.
E) The center of mass of the system of fragments will have a trajectory that depends on the number of fragments and their velocities right after the explosion.

Therefore, the correct option is A, B, and E.