Solve the all parts of given question:
Question: Over a time interval of 2.01 years, the velocity of a planet orbiting a distant star reverses direction, changing from +21.9 km/s to -24.4 km/s.
Part A: Find the total change in the planet's velocity (in m/s)?
Part B: Find 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 show work on how to solve above question!