How many times greater is the kinetic energy of the person when biking than when walking? Ignore the mass of the bike.

(a) 1.7;

(b) 3;

(c) 6;

(d) 9.

On flat ground, a 70-kg person requires about 300 W of metabolic power to walk at a steady pace of 5.0 km/h(1.4 m/s). Using the same metabolic power output, that person can bicycle over the same ground at 15 km/h.