Question

Superman (120.0 kg), Aquaman (100.0 kg) and Batman (90.0 kg) are all standing on a 12.00 m long thin log (5.00 kg) whose left end sits at rest in the water right next to shore (taken to be x = 0), arguing over who has the best movie. Wonder Woman stands quietly on the shore. Superman is 2.00 m from the left end of the log. Aquaman is 1.00 m to the right of Superman and Batman is 4.00 m from the right end of the log.  

(a) Soon, Wonder Woman gently pushes the log away from shore, giving it a speed of 1.50 m/s. What is the center of mass of the superhero-log system at t = 2.00 s, when Wonder Woman stops the log from moving?

(b) Now that the log is at rest again, the three superheroes move around the log. (All distances are given from the perspective of the log.) Batman moves 4.00 m to the left. Aquaman moves two meters to the right, and Superman moves 7.00 m to the right. What are the new coordinates of Batman, Superman, Aquaman and the log after everyone has moved to their new location?

(c) If it takes everyone 4.00 s to move to their new location, what is the average velocity for each of them over that period of time? (Don't forget about the log!)

Answer 1