Solve the following question given below:
Question: An astronaut on a distant planet wants to determine its acceleration due to gravity. The astronaut throws a rock straight up with a velocity of +10 m/s and measures a time of 18.6 s before the rock returns to his hand.
Part A: What is the acceleration (magnitude and direction) due to gravity on this planet? (Indicate direction by the sign of the acceleration.)
Please show work and steps to find the acceleration (magnitude and direction) due to gravity on this planet I think I have the answer just not positive.