A NASA space probe is traveling from the Earth (average orbital radius, rE = 149.6 x 106 km; period of revolution, TE = 1.00 yrs) to Mars (average orbital radius, rM = 227.9 x 106 km; period of revolution, TM = 1.881 yrs). Treat the orbit of Mars and Earth as circles, with the Sun at the center. The trip takes tEM = 9.5 months. The average length of a month is 30.436875 days. vE = 29800 and vM = 24140. Assume that the probe starts at rest on the surface of the Earth and comes to rest on the surface of Mars. Calculate the average tangential, apt in m/s^2, of the probe over its journey.