When a falling firecracker explodes, the momenta of its pieces _______.
A.vectorally add to equal the initial momentum of the firecracker
B. are conserved only if the fragments eject in one direction
C.illustrate a case in which momentum is not conserved
D.disintegrate
Conservation of Momentum does not have exceptions. There are no external forces on this system. Its momentum does not change. Period. A
To determine the correct answer, we need to understand the principle of conservation of momentum. According to Newton's third law, the law of conservation of momentum states that in the absence of any external forces, the total momentum of a system remains constant.
When a firecracker explodes, it experiences an internal explosion force, which leads to the breaking apart of the firecracker into multiple pieces. The forces acting on these pieces are internal forces, and the law of conservation of momentum applies to these forces as well.
Now let's analyze the answer choices based on this information:
A. Vectorally add to equal the initial momentum of the firecracker:
This answer is correct. According to the conservation of momentum, the momenta of the individual pieces of the firecracker will vectorally add up to equal the initial momentum of the firecracker before the explosion. This means the total momentum of the fragments will be equal to the momentum before the explosion.
B. Are conserved only if the fragments eject in one direction:
This answer is incorrect. Conservation of momentum does not require the fragments to eject in only one direction. The direction of the fragments can vary, as long as the vector sum of their momenta is equal to the initial momentum of the firecracker.
C. Illustrate a case in which momentum is not conserved:
This answer is incorrect. The conservation of momentum holds true in this scenario. The momenta of the pieces may change due to the explosion, but the total momentum remains constant.
D. Disintegrate:
This is not a valid answer choice. It does not provide any explanation regarding the conservation of momentum or how the momenta of the pieces behave.
Therefore, the correct answer is A. The momenta of the pieces vectorally add to equal the initial momentum of the firecracker.