What is the reasonable estimate of the average kinetic energy of an athlete during a 100m race that takes 10s ?

Which object is most likely represented by a dot?

Find v(t), given acceleration a(t)=7j and initial velocity v(0)=k

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?