Four persons K, L, M, and N are initially at the four corners of a square of side 'd'. Each person now moves with a uniform speed of 'v' in such a way that K always moves directly towards L, L directly towards M, M directly towards N and N directly towards K. At what time will the four persons meet? A truck is moving 60 mph, I throw a ball when inside the truck at 60 mph in the opposite direction of the vehicle's motion. How would the ball travel?