Over a time interval of 1.98 years, the velocity of a planet orbiting a distant star reverses direction, changing from +21.9 km/s to -17.2 km/s. Find (a) the total change in the planet's velocity (in m/s) and (b) its average acceleration (in m/s2) during this interval. Include the correct algebraic sign with your answers to convey the directions of the velocity and the acceleration.

Please help!

3 answers

Or options r
Ms susie -- I doubt if you know anything about physics. Please do not answer any questions unless you are absolutely sure you are right.
I did one like that recently
https://www.jiskha.com/display.cgi?id=1517378428