In the classic computer game Portal, the player is asked to solve puzzles with the use of a "portal device".This device can create two connected por- tals on, for example, the floor and a wall. An object entering one portal with speed v will exit the other with the same speed. The game's narrator helpfully ex- plains that "Forward momentum, a prod- uct of mass and velocity, is conserved be- tween portals. In layman's terms: speedy thing goes in; speedy thing comes out."(a) Is this an accurate statement of the law of conservation of momentum? Does such a device conserve momentum, as the narrator states? If not, why not?(b) Does this portal device conserve kinetic energy?(c) Does it conserve total energy (kinetic plus potential)?

1. In the classic computer game Portal, the player is asked to solve puzzles with the use of a "portal device". This device can create two connected por- tals on, for example, the floor and a wall. An object entering one portal with speed v will exit the other with the same speed. The game's narrator helpfully ex- plains that "Forward momentum, a prod- uct of mass and velocity, is conserved be- tween portals. In layman's terms: speedy thing goes in; speedy thing comes out." (a) Is this an accurate statement of the law of conservation of momentum? Does such a device conserve momentum, as the narrator states? If not, why not? (b) Does this portal device conserve kinetic energy? (c) Does it conserve total energy (kinetic plus potential)