Influenced by the gravitational pull of a distant star, the velocity of an asteroid changes from from +19.0 km/s to −19.4 km/s over a period of 1.85 years.

Question

(a) What is the total change in the asteroid's velocity? (Indicate the direction with the sign of your answer.)

(b) What is the asteroid's average acceleration during this interval (Indicate the direction with the sign of your answer.)

Answer 1

clearly, it is (-19.4 - 19.0)km/s

since acceleration is change in v over time, it is

(-19.4 - 19.0)km/s
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1.85 yr

Of course, that gives a value in units of km/s-yr, probably not one you want to wind up with. Convert yr to seconds, if you want km/s^2

Answer 2

-36000