Ariver has a steady speed of 0.500 m/s. a student swims upstream a distance of 1.00 km and swims back to the starting point. if the student can swim at a speed of 1.20 m/s in still water, how long does the trip take? compare this with the time the trip would take if the water were still.

Let's find the time to swim upstream. time = distance / speed time = 1000 m / 0.70 m/s time = 1428.6 seconds Let's find the time to swim downstream. time = distance / speed time = 1000 m / 1.70 m/s time = 588.2 seconds The total time is 2016.8 seconds which is 33.6 minutes. Let's find the time to swim 2.00 km in still water. time = distance / speed time = 2000 m / 1.20 m/s time = 1666.7 seconds The total time to swim in still water is 1666.7 seconds which is 27.8 minutes. The swimmer could complete the 2.00 km swim 5.8 minutes faster in still water.

//(b) both involve the use of levers;

The fertilized egg  begins to develop into a hollow ball of cells called the blastocyst.