You stand on a balcony and throw a bouncy ball upwards with 7.2 j of kinetic energy the ball has 8.3 j of gravitational potential energy when it left your hand how much total energy does the ball have as it leaves your hand

15.5 J

Explanation:

The total (mechanical) energy of an object is given by

E = K + U

where

K is the kinetic energy

U is the gravitational potential energy

The ball in the problem, when it left the hand, has:

K = 7.2 J (kinetic energy)

U = 8.3 J (potential energy)

So, its total mechanical energy is

E = 7.2 + 8.3 = 15.5 J

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