Please help me with 2.2 and 2.3

Amoving electron has kinetic energy k1. after a net amount of work w has been done on it, the electron is moving one-quarter as fast in the opposite direction. (a) find w in terms of k1. (b) does your answer depend on the final direction of the electron's motion?

When the displacement of a mass on a spring is 12a the half of the amplitude, what fraction of the mechanical energy is kinetic energy? at what displacement, as a fraction of a, is the mechanical energy half kinetic and half potential?

When measuring volume, why is it important to use the correct tools and units to attain the greatest accuracy? use specific examples from the lab to support your answer. (5 points)