Agamma-ray photon changes into a proton-antiproton pair. ignoring momentum conservation, what must have been thewavelength of the photon (a) if the pair is stationary after creation, and (b) if each moves off at 0.6c. perpendicular to themotion of the photon? (c) assume that these interactions occur as the photon encounters a lead plate and that a leadnucleus participates in momentum conservation. in each case, what fraction of the photon’s energy must be absorbed bya lead nucleus?

Is a  vector quantity  that refers to "the rate at which an object changes its position." imagine a person moving rapidly - one step forward and one step back - always returning to the original starting position. while this might result in a frenzy of activity, it would result in a zero velocity. because the person always returns to the original position, the motion would never result in a change in position. since velocity is defined as the rate at which the position changes, this motion results in zero velocity. if a person in motion wishes to maximize their velocity, then that person must make every effort to maximize the amount that they are displaced from their original position. every step must go into moving that person further from where he or she started. for certain, the person should never change directions and begin to return to the starting position.

If your workout exceeds an hour you should substitute "a sports drink" for water.hope my answer has you : )