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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.

• Please I really need help with this problem!!! - ,

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.