The speedof a boat in still water is v. the boat is to make a round-trip ina river whose current travels at speed u. derive a formula for thetime needed to make a round trip of total distance d if the boatmakes the round trip by moving (a) upstream and back downstream,(b) directly across the river and back. we must assume u < v; why?

b) 10 minutes

girls stopped for 10 minutes.

jupiter is the largest planet in our solar system, having a mass and radius that are respectively, 318 and 11.2 times that of earth. suppose that an object falls from rest near the surface of each planet and that the acceleration due to gravity remains constant during the fall. each object falls the same distance before striking the ground. determine the ratio of the time of fall on jupiter to that on earth.