Ineed ! a 2.0 kilogram toy cannon is at rest on a frictionless surface. a. remote triggering device causes a 0.005 kilogram projectile to be fired from the cannon. which of the following equations best describes this system after the cannon is fired? a) speed of cannon + speed of projectile=0b) mass of cannon + mass of projectile = 0 c) velocity of cannon + velocity of projectile=0d)momentum of cannon + momentum of projectile= 0 d is the correct answer but i need an explanation of why it is the right answer

D) momentum of cannon + momentum of projectile= 0

Explanation:

The law of conservation of momentum states that the total momentum of an isolated system is constant.

In this case, the system cannon+projectile can be considered as isolated, because no external forces act on it (in fact, the surface is frictionless, so there is no friction acting on the cannon). Therefore, the total momentum of the two objects (cannon+projectile) must be equal before and after the firing:

But the initial momentum is zero, because at the beginning both the cannon and the projectile are at rest:

So the final momentum, which is sum of the momentum of the cannon and of the projectile, must also be zero:

.) the observation by semmelweis that more mothers died of childbed fever when their doctors also worked in the morgue

answer(20) psi;