PHYSICS....confused again. I think the first part is .008 but I am unsure.?

Question

In 1998, NASA launched Deep-Space 1 (DS-1), a spacecraft that successfully flew by the asteroid named 1992 KD (which orbits the sun millions of miles from the earth). The propulsion system of DS-1 worked by ejecting high-speed argon ions out the rear of the engine. The engine slowly increases the velocity of DS-1 by about 19.0 m/s per day.
(a) How much time (in days) would it take to increase the velocity of DS-1 by 13700 m/s?
days

(b) What was the acceleration of DS-1 (in m/s2)?
m/s2

Answer 1

Let us first calculate the acceleration provided by the ion propulsion engine. Since it increases the velocity by 19.7m/s in a day, we can use v = u + at

19.7 = 0 + a.24 X 3600 = 86400a

a = 19.7/86400 = 0.000228 m/s


Now let us work out the number of days needed to make the velocity 13700 m/sec. We assume that the starting velocity is 0 (certainly not correct).

v = u + a.t

13700 = 19.7.t where t is in days.

t = 13700 / 19.7 = 695.4 days

A really good example of what a small engine can do.