Joe is setting up a test run for a new roller coaster. The coaster car and test dummy have a combined mass of 520 kg, and the portion of the coaster they are
testing drops from a hill into a circular loop 10.0 meters across. What is the minimum speed
the car must be going at the top of the loop? What is the minimum height the hill leading
into the loop must be (measured from the bottom of the loop to the top of the hill)?

Explanation:

and test dummy have a combined mass of 520 kg, and the portion of the coaster they are

testing drops from a hill into a circular loop 10.0 meters across. What is the minimum speed

the car must be going at the top of the loop? What is the minimum height the hill leading

into the loop must be (measured from the bottom of the loop to the top of the hill)?

when jerome paddle in flowing river towards east the net speed of jerome will increase

so the net speed of jerome will be given as

now the speed of paul will be same as it is given as he is running on the ground

so

so here we can say since the speed of jerome is more so he will win the race

now as we know the distance so the time difference is given as

so jerome will reach first and the time difference will be 203.55 s or 3.4 min